DataFrame#
Most DataFrame methods are lazy, meaning that they do not execute computation immediately when invoked. Instead, these operations are enqueued in the DataFrame's internal query plan, and are only executed when Execution DataFrame methods are called. Learn more about DataFrames in Daft User Guide.
DataFrame #
DataFrame(builder: LogicalPlanBuilder)
A Daft DataFrame is a table of data.
It has columns, where each column has a type and the same number of items (rows) as all other columns.
Constructs a DataFrame according to a given LogicalPlan.
Users are expected instead to call the classmethods on DataFrame to create a DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
plan | LogicalPlan describing the steps required to arrive at this DataFrame | required |
Methods:
Name | Description |
---|---|
__contains__ | Returns whether the column exists in the dataframe. |
__getitem__ | Gets a column from the DataFrame as an Expression ( |
__iter__ | Alias of |
__len__ | Returns the count of rows when dataframe is materialized. |
agg | Perform aggregations on this DataFrame. |
agg_concat | Performs a global list concatenation agg on the DataFrame. |
agg_list | Performs a global list agg on the DataFrame. |
agg_set | Performs a global set agg on the DataFrame (ignoring nulls). |
any_value | Returns an arbitrary value on this DataFrame. |
collect | Executes the entire DataFrame and materializes the results. |
concat | Concatenates two DataFrames together in a "vertical" concatenation. |
count | Performs a global count on the DataFrame. |
count_rows | Executes the Dataframe to count the number of rows. |
describe | Returns the Schema of the DataFrame, which provides information about each column, as a new DataFrame. |
distinct | Computes distinct rows, dropping duplicates. |
drop_nan | Drops rows that contains NaNs. If cols is None it will drop rows with any NaN value. |
drop_null | Drops rows that contains NaNs or NULLs. If cols is None it will drop rows with any NULL value. |
except_all | Returns the set difference of two DataFrames, considering duplicates. |
except_distinct | Returns the set difference of two DataFrames. |
exclude | Drops columns from the current DataFrame by name. |
explain | Prints the (logical and physical) plans that will be executed to produce this DataFrame. |
explode | Explodes a List column, where every element in each row's List becomes its own row, and all other columns in the DataFrame are duplicated across rows. |
filter | Filters rows via a predicate expression, similar to SQL |
groupby | Performs a GroupBy on the DataFrame for aggregation. |
intersect | Returns the intersection of two DataFrames. |
intersect_all | Returns the intersection of two DataFrames, including duplicates. |
into_partitions | Splits or coalesces DataFrame to |
iter_partitions | Begin executing this dataframe and return an iterator over the partitions. |
iter_rows | Return an iterator of rows for this dataframe. |
join | Column-wise join of the current DataFrame with an |
limit | Limits the rows in the DataFrame to the first |
max | Performs a global max on the DataFrame. |
mean | Performs a global mean on the DataFrame. |
melt | Alias for unpivot. |
min | Performs a global min on the DataFrame. |
num_partitions | |
pipe | Apply the function to this DataFrame. |
pivot | Pivots a column of the DataFrame and performs an aggregation on the values. |
repartition | Repartitions DataFrame to |
sample | Samples a fraction of rows from the DataFrame. |
schema | Returns the Schema of the DataFrame, which provides information about each column, as a Python object. |
select | Creates a new DataFrame from the provided expressions, similar to a SQL |
show | Executes enough of the DataFrame in order to display the first |
sort | Sorts DataFrame globally. |
stddev | Performs a global standard deviation on the DataFrame. |
sum | Performs a global sum on the DataFrame. |
summarize | Returns column statistics for the DataFrame. |
to_arrow | Converts the current DataFrame to a pyarrow Table. |
to_arrow_iter | Return an iterator of pyarrow recordbatches for this dataframe. |
to_dask_dataframe | Converts the current Daft DataFrame to a Dask DataFrame. |
to_pandas | Converts the current DataFrame to a pandas DataFrame. |
to_pydict | Converts the current DataFrame to a python dictionary. The dictionary contains Python lists of Python objects for each column. |
to_pylist | Converts the current Dataframe into a python list. |
to_ray_dataset | Converts the current DataFrame to a Ray Dataset which is useful for running distributed ML model training in Ray. |
to_torch_iter_dataset | Convert the current DataFrame into a |
to_torch_map_dataset | Convert the current DataFrame into a map-style Torch Dataset for use with PyTorch. |
transform | Apply a function that takes and returns a DataFrame. |
union | Returns the distinct union of two DataFrames. |
union_all | Returns the union of two DataFrames, including duplicates. |
union_all_by_name | Returns the union of two DataFrames, including duplicates, with columns matched by name. |
union_by_name | Returns the distinct union by name. |
unique | Computes distinct rows, dropping duplicates. |
unpivot | Unpivots a DataFrame from wide to long format. |
where | Filters rows via a predicate expression, similar to SQL |
with_column | Adds a column to the current DataFrame with an Expression, equivalent to a |
with_column_renamed | Renames a column in the current DataFrame. |
with_columns | Adds columns to the current DataFrame with Expressions, equivalent to a |
with_columns_renamed | Renames multiple columns in the current DataFrame. |
write_csv | Writes the DataFrame as CSV files, returning a new DataFrame with paths to the files that were written. |
write_deltalake | Writes the DataFrame to a Delta Lake table, returning a new DataFrame with the operations that occurred. |
write_iceberg | Writes the DataFrame to an Iceberg table, returning a new DataFrame with the operations that occurred. |
write_lance | Writes the DataFrame to a Lance table. |
write_parquet | Writes the DataFrame as parquet files, returning a new DataFrame with paths to the files that were written. |
write_sink | Writes the DataFrame to the given DataSink. |
Attributes:
Name | Type | Description |
---|---|---|
column_names | List[str] | Returns column names of DataFrame as a list of strings. |
columns | List[Expression] | Returns column of DataFrame as a list of Expressions. |
Source code in daft/dataframe/dataframe.py
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column_names #
column_names: List[str]
Returns column names of DataFrame as a list of strings.
Returns:
Type | Description |
---|---|
List[str] | List[str]: Column names of this DataFrame. |
columns #
columns: List[Expression]
Returns column of DataFrame as a list of Expressions.
Returns:
Type | Description |
---|---|
List[Expression] | List[Expression]: Columns of this DataFrame. |
__contains__ #
__contains__(col_name: str) -> bool
Returns whether the column exists in the dataframe.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
col_name | str | column name | required |
Returns:
Name | Type | Description |
---|---|---|
bool | bool | whether the column exists in the dataframe. |
Examples:
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Source code in daft/dataframe/dataframe.py
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__getitem__ #
__getitem__(
item: Union[slice, int, str, Iterable[Union[str, int]]],
) -> Union[Expression, DataFrame]
Gets a column from the DataFrame as an Expression (df["mycol"]
).
Source code in daft/dataframe/dataframe.py
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__iter__ #
__iter__() -> Iterator[Dict[str, Any]]
Alias of self.iter_rows()
with default arguments for convenient access of data.
Source code in daft/dataframe/dataframe.py
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__len__ #
__len__()
Returns the count of rows when dataframe is materialized.
If dataframe is not materialized yet, raises a runtime error.
Returns:
Name | Type | Description |
---|---|---|
int | count of rows. |
Source code in daft/dataframe/dataframe.py
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agg #
agg(
*to_agg: Union[Expression, Iterable[Expression]],
) -> DataFrame
Perform aggregations on this DataFrame.
Allows for mixed aggregations for multiple columns and will return a single row that aggregated the entire DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*to_agg | Expression | aggregation expressions | () |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with aggregated results |
Examples:
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Source code in daft/dataframe/dataframe.py
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agg_concat #
agg_concat(*cols: ColumnInputType) -> DataFrame
Performs a global list concatenation agg on the DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns that are lists to concatenate | () |
Returns: DataFrame: Globally aggregated list. Should be a single row.
Source code in daft/dataframe/dataframe.py
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agg_list #
agg_list(*cols: ColumnInputType) -> DataFrame
Performs a global list agg on the DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns to form into a list | () |
Returns: DataFrame: Globally aggregated list. Should be a single row.
Source code in daft/dataframe/dataframe.py
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agg_set #
agg_set(*cols: ColumnInputType) -> DataFrame
Performs a global set agg on the DataFrame (ignoring nulls).
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns to form into a set | () |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Globally aggregated set. Should be a single row. |
Source code in daft/dataframe/dataframe.py
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any_value #
any_value(*cols: ColumnInputType) -> DataFrame
Returns an arbitrary value on this DataFrame.
Values for each column are not guaranteed to be from the same row.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns to get an arbitrary value from | () |
Returns: DataFrame: DataFrame with any values.
Source code in daft/dataframe/dataframe.py
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collect #
collect(num_preview_rows: Optional[int] = 8) -> DataFrame
Executes the entire DataFrame and materializes the results.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
num_preview_rows | Optional[int] | Number of rows to preview. Defaults to 8. | 8 |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with materialized results. |
Note
This call is blocking and will execute the DataFrame when called
Source code in daft/dataframe/dataframe.py
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concat #
Concatenates two DataFrames together in a "vertical" concatenation.
The resulting DataFrame has number of rows equal to the sum of the number of rows of the input DataFrames.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
other | DataFrame | other DataFrame to concatenate | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with rows from |
Note
DataFrames being concatenated must have exactly the same schema. You may wish to use the df.select() and expr.cast() methods to ensure schema compatibility before concatenation.
Source code in daft/dataframe/dataframe.py
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count #
count(*cols: ColumnInputType) -> DataFrame
Performs a global count on the DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns to count | () |
Returns: DataFrame: Globally aggregated count. Should be a single row.
Examples:
If no columns are specified (i.e. in the case you call df.count()
), or only the literal string "", this functions very similarly to a COUNT() operation in SQL and will return a new dataframe with a single column with the name "count".
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However, specifying some column names would instead change the behavior to count all non-null values, similar to a SQL command for SELECT COUNT(foo), COUNT(bar) FROM df
. Also, using df.count(col("*"))
will expand out into count() for each column.
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Source code in daft/dataframe/dataframe.py
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count_rows #
count_rows() -> int
Executes the Dataframe to count the number of rows.
Returns:
Name | Type | Description |
---|---|---|
int | int | count of the number of rows in this DataFrame. |
Source code in daft/dataframe/dataframe.py
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describe #
describe() -> DataFrame
Returns the Schema of the DataFrame, which provides information about each column, as a new DataFrame.
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | A dataframe where each row is a column name and its corresponding type. |
Examples:
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Source code in daft/dataframe/dataframe.py
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distinct #
distinct() -> DataFrame
Computes distinct rows, dropping duplicates.
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame that has only distinct rows. |
Examples:
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Source code in daft/dataframe/dataframe.py
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drop_nan #
drop_nan(*cols: ColumnInputType)
Drops rows that contains NaNs. If cols is None it will drop rows with any NaN value.
If column names are supplied, it will drop only those rows that contains NaNs in one of these columns.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | str | column names by which rows containing nans/NULLs should be filtered | () |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame without NaNs in specified/all columns |
Examples:
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Source code in daft/dataframe/dataframe.py
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drop_null #
drop_null(*cols: ColumnInputType)
Drops rows that contains NaNs or NULLs. If cols is None it will drop rows with any NULL value.
If column names are supplied, it will drop only those rows that contains NULLs in one of these columns.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | str | column names by which rows containing nans should be filtered | () |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame without missing values in specified/all columns |
Examples:
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Source code in daft/dataframe/dataframe.py
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except_all #
Returns the set difference of two DataFrames, considering duplicates.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
other | DataFrame | DataFrame to except with | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with the set difference of the two DataFrames, considering duplicates |
Examples:
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Source code in daft/dataframe/dataframe.py
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except_distinct #
Returns the set difference of two DataFrames.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
other | DataFrame | DataFrame to except with | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with the set difference of the two DataFrames |
Examples:
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Source code in daft/dataframe/dataframe.py
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exclude #
exclude(*names: str) -> DataFrame
Drops columns from the current DataFrame by name.
This is equivalent of performing a select with all the columns but the ones excluded.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*names | str | names to exclude | () |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with some columns excluded. |
Examples:
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Source code in daft/dataframe/dataframe.py
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explain #
explain(
show_all: bool = False,
format: str = "ascii",
simple: bool = False,
file: Optional[IOBase] = None,
) -> Any
Prints the (logical and physical) plans that will be executed to produce this DataFrame.
Defaults to showing the unoptimized logical plan. Use show_all=True
to show the unoptimized logical plan, the optimized logical plan, and the physical plan.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
show_all | bool | Whether to show the optimized logical plan and the physical plan in addition to the unoptimized logical plan. | False |
format | str | The format to print the plan in. one of 'ascii' or 'mermaid' | 'ascii' |
simple | bool | Whether to only show the type of op for each node in the plan, rather than showing details of how each op is configured. | False |
file | Optional[IOBase] | Location to print the output to, or defaults to None which defaults to the default location for print (in Python, that should be sys.stdout) | None |
Source code in daft/dataframe/dataframe.py
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explode #
explode(*columns: ColumnInputType) -> DataFrame
Explodes a List column, where every element in each row's List becomes its own row, and all other columns in the DataFrame are duplicated across rows.
If multiple columns are specified, each row must contain the same number of items in each specified column.
Exploding Null values or empty lists will create a single Null entry (see example below).
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*columns | ColumnInputType | columns to explode | () |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with exploded column |
Examples:
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Source code in daft/dataframe/dataframe.py
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filter #
filter(predicate: Union[Expression, str]) -> DataFrame
Filters rows via a predicate expression, similar to SQL WHERE
.
Alias for daft.DataFrame.where.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
predicate | Expression | expression that keeps row if evaluates to True. | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Filtered DataFrame. |
Tip
See also .where(predicate)
Source code in daft/dataframe/dataframe.py
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groupby #
groupby(
*group_by: ManyColumnsInputType,
) -> GroupedDataFrame
Performs a GroupBy on the DataFrame for aggregation.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*group_by | Union[str, Expression] | columns to group by | () |
Returns:
Name | Type | Description |
---|---|---|
GroupedDataFrame | GroupedDataFrame | DataFrame to Aggregate |
Examples:
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Source code in daft/dataframe/dataframe.py
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intersect #
Returns the intersection of two DataFrames.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
other | DataFrame | DataFrame to intersect with | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with the intersection of the two DataFrames |
Examples:
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Source code in daft/dataframe/dataframe.py
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intersect_all #
Returns the intersection of two DataFrames, including duplicates.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
other | DataFrame | DataFrame to intersect with | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with the intersection of the two DataFrames, including duplicates |
Examples:
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Source code in daft/dataframe/dataframe.py
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into_partitions #
into_partitions(num: int) -> DataFrame
Splits or coalesces DataFrame to num
partitions. Order is preserved.
This will naively greedily split partitions in a round-robin fashion to hit the targeted number of partitions. The number of rows/size in a given partition is not taken into account during the splitting.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
num | int | number of target partitions. | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Dataframe with |
Examples:
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Source code in daft/dataframe/dataframe.py
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iter_partitions #
iter_partitions(
results_buffer_size: Union[
Optional[int], Literal["num_cpus"]
] = "num_cpus",
) -> Iterator[
Union[MicroPartition, ObjectRef[MicroPartition]]
]
Begin executing this dataframe and return an iterator over the partitions.
Each partition will be returned as a daft.recordbatch object (if using Python runner backend) or a ray ObjectRef (if using Ray runner backend).
Parameters:
Name | Type | Description | Default |
---|---|---|---|
results_buffer_size | Union[Optional[int], Literal['num_cpus']] | how many partitions to allow in the results buffer (defaults to the total number of CPUs available on the machine). | 'num_cpus' |
A quick note on configuring asynchronous/parallel execution using results_buffer_size
.
The results_buffer_size
kwarg controls how many results Daft will allow to be in the buffer while iterating. Once this buffer is filled, Daft will not run any more work until some partition is consumed from the buffer.
- Increasing this value means the iterator will consume more memory and CPU resources but have higher throughput
- Decreasing this value means the iterator will consume lower memory and CPU resources, but have lower throughput
- Setting this value to
None
means the iterator will consume as much resources as it deems appropriate per-iteration
The default value is the total number of CPUs available on the current machine.
Examples:
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Source code in daft/dataframe/dataframe.py
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iter_rows #
iter_rows(
results_buffer_size: Union[
Optional[int], Literal["num_cpus"]
] = "num_cpus",
column_format: Literal["python", "arrow"] = "python",
) -> Iterator[Dict[str, Any]]
Return an iterator of rows for this dataframe.
Each row will be a Python dictionary of the form { "key" : value, ...}
. If you are instead looking to iterate over entire partitions of data, see df.iter_partitions()
.
By default, Daft will convert the columns to Python lists for easy consumption. Datatypes with Python equivalents will be converted accordingly, e.g. timestamps to datetime, tensors to numpy arrays. For nested data such as List or Struct arrays, however, this can be expensive. You may wish to set column_format
to "arrow" such that the nested data is returned as Arrow scalars.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
results_buffer_size | Union[Optional[int], Literal['num_cpus']] | how many partitions to allow in the results buffer (defaults to the total number of CPUs available on the machine). | 'num_cpus' |
column_format | Literal['python', 'arrow'] | the format of the columns to iterate over. One of "python" or "arrow". Defaults to "python". | 'python' |
A quick note on configuring asynchronous/parallel execution using results_buffer_size
.
The results_buffer_size
kwarg controls how many results Daft will allow to be in the buffer while iterating. Once this buffer is filled, Daft will not run any more work until some partition is consumed from the buffer.
- Increasing this value means the iterator will consume more memory and CPU resources but have higher throughput
- Decreasing this value means the iterator will consume lower memory and CPU resources, but have lower throughput
- Setting this value to
None
means the iterator will consume as much resources as it deems appropriate per-iteration
The default value is the total number of CPUs available on the current machine.
Examples:
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|
See also df.iter_partitions()
: iterator over entire partitions instead of single rows
Source code in daft/dataframe/dataframe.py
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|
join #
join(
other: DataFrame,
on: Optional[
Union[List[ColumnInputType], ColumnInputType]
] = None,
left_on: Optional[
Union[List[ColumnInputType], ColumnInputType]
] = None,
right_on: Optional[
Union[List[ColumnInputType], ColumnInputType]
] = None,
how: Literal[
"inner",
"inner",
"left",
"right",
"outer",
"anti",
"semi",
"cross",
] = "inner",
strategy: Optional[
Literal["hash", "sort_merge", "broadcast"]
] = None,
prefix: Optional[str] = None,
suffix: Optional[str] = None,
) -> DataFrame
Column-wise join of the current DataFrame with an other
DataFrame, similar to a SQL JOIN
.
If the two DataFrames have duplicate non-join key column names, "right." will be prepended to the conflicting right columns. You can change the behavior by passing either (or both) prefix
or suffix
to the function. If prefix
is passed, it will be prepended to the conflicting right columns. If suffix
is passed, it will be appended to the conflicting right columns.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
other | DataFrame | the right DataFrame to join on. | required |
on | Optional[Union[List[ColumnInputType], ColumnInputType]] | key or keys to join on [use if the keys on the left and right side match.]. Defaults to None. | None |
left_on | Optional[Union[List[ColumnInputType], ColumnInputType]] | key or keys to join on left DataFrame. Defaults to None. | None |
right_on | Optional[Union[List[ColumnInputType], ColumnInputType]] | key or keys to join on right DataFrame. Defaults to None. | None |
how | str | what type of join to perform; currently "inner", "left", "right", "outer", "anti", "semi", and "cross" are supported. Defaults to "inner". | 'inner' |
strategy | Optional[str] | The join strategy (algorithm) to use; currently "hash", "sort_merge", "broadcast", and None are supported, where None chooses the join strategy automatically during query optimization. The default is None. | None |
suffix | Optional[str] | Suffix to add to the column names in case of a name collision. Defaults to "". | None |
prefix | Optional[str] | Prefix to add to the column names in case of a name collision. Defaults to "right.". | None |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Joined DataFrame. |
Raises:
Type | Description |
---|---|
ValueError | if |
ValueError | if |
Note
Although self joins are supported, we currently duplicate the logical plan for the right side and recompute the entire tree. Caching for this is on the roadmap.
Examples:
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|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
|
Source code in daft/dataframe/dataframe.py
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|
limit #
limit(num: int) -> DataFrame
Limits the rows in the DataFrame to the first N
rows, similar to a SQL LIMIT
.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
num | int | maximum rows to allow. | required |
eager | bool | whether to maximize for latency (time to first result) by eagerly executing only one partition at a time, or throughput by executing multiple limits at a time | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Limited DataFrame |
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 |
|
Source code in daft/dataframe/dataframe.py
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|
max #
max(*cols: ColumnInputType) -> DataFrame
Performs a global max on the DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns to max | () |
Returns: DataFrame: Globally aggregated max. Should be a single row.
Source code in daft/dataframe/dataframe.py
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|
mean #
mean(*cols: ColumnInputType) -> DataFrame
Performs a global mean on the DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns to mean | () |
Returns: DataFrame: Globally aggregated mean. Should be a single row.
Source code in daft/dataframe/dataframe.py
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|
melt #
melt(
ids: ManyColumnsInputType,
values: ManyColumnsInputType = [],
variable_name: str = "variable",
value_name: str = "value",
) -> DataFrame
Alias for unpivot.
Tip
See also unpivot
Source code in daft/dataframe/dataframe.py
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|
min #
min(*cols: ColumnInputType) -> DataFrame
Performs a global min on the DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns to min | () |
Returns: DataFrame: Globally aggregated min. Should be a single row.
Source code in daft/dataframe/dataframe.py
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|
num_partitions #
num_partitions() -> int
Source code in daft/dataframe/dataframe.py
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|
pipe #
pipe(
function: Callable[Concatenate[DataFrame, P], T],
*args: args,
**kwargs: kwargs,
) -> T
Apply the function to this DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
function | Callable[Concatenate[DataFrame, P], T] | Function to apply. | required |
*args | args | Positional arguments to pass to the function. | () |
**kwargs | kwargs | Keyword arguments to pass to the function. | {} |
Returns:
Type | Description |
---|---|
T | Result of applying the function on this DataFrame. |
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 |
|
Source code in daft/dataframe/dataframe.py
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|
pivot #
pivot(
group_by: ManyColumnsInputType,
pivot_col: ColumnInputType,
value_col: ColumnInputType,
agg_fn: str,
names: Optional[List[str]] = None,
) -> DataFrame
Pivots a column of the DataFrame and performs an aggregation on the values.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
group_by | ManyColumnsInputType | columns to group by | required |
pivot_col | Union[str, Expression] | column to pivot | required |
value_col | Union[str, Expression] | column to aggregate | required |
agg_fn | str | aggregation function to apply | required |
names | Optional[List[str]] | names of the pivoted columns | None |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with pivoted columns |
Note
You may wish to provide a list of distinct values to pivot on, which is more efficient as it avoids a distinct operation. Without this list, Daft will perform a distinct operation on the pivot column to determine the unique values to pivot on.
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
|
Source code in daft/dataframe/dataframe.py
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|
repartition #
repartition(
num: Optional[int], *partition_by: ColumnInputType
) -> DataFrame
Repartitions DataFrame to num
partitions.
If columns are passed in, then DataFrame will be repartitioned by those, otherwise random repartitioning will occur.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
num | Optional[int] | Number of target partitions; if None, the number of partitions will not be changed. | required |
*partition_by | Union[str, Expression] | Optional columns to partition by. | () |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Repartitioned DataFrame. |
This function will globally shuffle your data, which is potentially a very expensive operation.
If instead you merely wish to "split" or "coalesce" partitions to obtain a target number of partitions, you mean instead wish to consider using DataFrame.into_partitions which avoids shuffling of data in favor of splitting/coalescing adjacent partitions where appropriate.
Examples:
1 2 3 4 5 |
|
Source code in daft/dataframe/dataframe.py
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|
sample #
sample(
fraction: float,
with_replacement: bool = False,
seed: Optional[int] = None,
) -> DataFrame
Samples a fraction of rows from the DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
fraction | float | fraction of rows to sample. | required |
with_replacement | bool | whether to sample with replacement. Defaults to False. | False |
seed | Optional[int] | random seed. Defaults to None. | None |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with a fraction of rows. |
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 |
|
Source code in daft/dataframe/dataframe.py
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|
schema #
schema() -> Schema
Returns the Schema of the DataFrame, which provides information about each column, as a Python object.
Returns:
Name | Type | Description |
---|---|---|
Schema | Schema | schema of the DataFrame |
Source code in daft/dataframe/dataframe.py
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|
select #
select(*columns: ColumnInputType) -> DataFrame
Creates a new DataFrame from the provided expressions, similar to a SQL SELECT
.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*columns | Union[str, Expression] | columns to select from the current DataFrame | () |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | new DataFrame that will select the passed in columns |
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
|
Source code in daft/dataframe/dataframe.py
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|
show #
show(
n: int = 8,
format: Optional[PreviewFormat] = None,
verbose: bool = False,
max_width: int = 30,
align: PreviewAlign = "left",
columns: Optional[List[PreviewColumn]] = None,
) -> None
Executes enough of the DataFrame in order to display the first n
rows.
If IPython is installed, this will use IPython's display
utility to pretty-print in a notebook/REPL environment. Otherwise, this will fall back onto a naive Python print
.
If no format is given, then daft's truncating preview format is used. - The output is a 'fancy' table with rounded corners. - Headers contain the column's data type. - Columns are truncated to 30 characters. - The table's overall width is limited to 10 columns.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
n | int | number of rows to show. Defaults to 8. | 8 |
format | PreviewFormat | the box-drawing format e.g. "fancy" or "markdown". | None |
**options | keyword arguments to modify the formatting, please see the options section. | required |
Note
This call is blocking and will execute the DataFrame when called
Examples:
1 2 3 4 5 6 |
|
Usage
- If columns are given, their length MUST match the schema.
- If columns are given, their settings override any global settings.
Source code in daft/dataframe/dataframe.py
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|
sort #
sort(
by: Union[ColumnInputType, List[ColumnInputType]],
desc: Union[bool, List[bool]] = False,
nulls_first: Optional[Union[bool, List[bool]]] = None,
) -> DataFrame
Sorts DataFrame globally.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
column | Union[ColumnInputType, List[ColumnInputType]] | column to sort by. Can be | required |
desc | Union[bool, List[bool]) | Sort by descending order. Defaults to False. | False |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Sorted DataFrame. |
Note
- Since this a global sort, this requires an expensive repartition which can be quite slow.
- Supports multicolumn sorts and can have unique
descending
flag per column.
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
|
You can also sort by multiple columns, and specify the 'descending' flag for each column:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 |
|
You can also specify null positioning (first/last) for each column
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 |
|
Parameters:
Name | Type | Description | Default |
---|---|---|---|
column | Union[ColumnInputType, List[ColumnInputType]] | column to sort by. Can be | required |
desc | Union[bool, List[bool]) | Sort by descending order. Defaults to False. | False |
nulls_first | Union[bool, List[bool]) | Sort by nulls first. Defaults to nulls being treated as the greatest value. | None |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Sorted DataFrame. |
Source code in daft/dataframe/dataframe.py
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|
stddev #
stddev(*cols: ColumnInputType) -> DataFrame
Performs a global standard deviation on the DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns to stddev | () |
Returns: DataFrame: Globally aggregated standard deviation. Should be a single row.
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 |
|
Source code in daft/dataframe/dataframe.py
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|
sum #
sum(*cols: ManyColumnsInputType) -> DataFrame
Performs a global sum on the DataFrame.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
*cols | Union[str, Expression] | columns to sum | () |
Returns: DataFrame: Globally aggregated sums. Should be a single row.
Source code in daft/dataframe/dataframe.py
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|
summarize #
summarize() -> DataFrame
Returns column statistics for the DataFrame.
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | new DataFrame with the computed column statistics. |
Source code in daft/dataframe/dataframe.py
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|
to_arrow #
to_arrow() -> Table
Converts the current DataFrame to a pyarrow Table.
If results have not computed yet, collect will be called.
Returns:
Type | Description |
---|---|
Table | pyarrow.Table: pyarrow Table converted from a Daft DataFrame |
Note
This call is blocking and will execute the DataFrame when called
Source code in daft/dataframe/dataframe.py
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|
to_arrow_iter #
to_arrow_iter(
results_buffer_size: Union[
Optional[int], Literal["num_cpus"]
] = "num_cpus",
) -> Iterator[RecordBatch]
Return an iterator of pyarrow recordbatches for this dataframe.
Source code in daft/dataframe/dataframe.py
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|
to_dask_dataframe #
to_dask_dataframe(
meta: Union[
DataFrame,
Series,
Dict[str, Any],
Iterable[Any],
Tuple[Any],
None,
] = None,
) -> DataFrame
Converts the current Daft DataFrame to a Dask DataFrame.
The returned Dask DataFrame will use Dask-on-Ray to execute operations on a Ray cluster.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
meta | Union[DataFrame, Series, Dict[str, Any], Iterable[Any], Tuple[Any], None] | An empty pandas DataFrameor Series that matches the dtypes and column names of the stream. This metadata is necessary for many algorithms in dask dataframe to work. For ease of use, some alternative inputs are also available. Instead of a DataFrame, a dict of | None |
Returns:
Type | Description |
---|---|
DataFrame | dask.DataFrame: A Dask DataFrame stored on a Ray cluster. |
Note
This function can only work if Daft is running using the RayRunner.
Source code in daft/dataframe/dataframe.py
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|
to_pandas #
to_pandas(
coerce_temporal_nanoseconds: bool = False,
) -> DataFrame
Converts the current DataFrame to a pandas DataFrame.
If results have not computed yet, collect will be called.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
coerce_temporal_nanoseconds | bool | Whether to coerce temporal columns to nanoseconds. Only applicable to pandas version >= 2.0 and pyarrow version >= 13.0.0. Defaults to False. See | False |
Returns:
Type | Description |
---|---|
DataFrame | pandas.DataFrame: pandas DataFrame converted from a Daft DataFrame |
Note
This call is blocking and will execute the DataFrame when called
Source code in daft/dataframe/dataframe.py
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|
to_pydict #
to_pydict() -> Dict[str, List[Any]]
Converts the current DataFrame to a python dictionary. The dictionary contains Python lists of Python objects for each column.
If results have not computed yet, collect will be called.
Returns:
Type | Description |
---|---|
Dict[str, List[Any]] | dict[str, list[Any]]: python dict converted from a Daft DataFrame |
Note
This call is blocking and will execute the DataFrame when called
Source code in daft/dataframe/dataframe.py
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|
to_pylist #
to_pylist() -> List[Any]
Converts the current Dataframe into a python list.
Returns:
Type | Description |
---|---|
List[Any] | List[dict[str, Any]]: List of python dict objects. |
Warning
This is a convenience method over DataFrame.iter_rows(). Users should prefer using .iter_rows()
directly instead for lower memory utilization if they are streaming rows out of a DataFrame and don't require full materialization of the Python list.
Examples:
1 2 3 4 5 |
|
See also
df.iter_rows(): streaming iterator over individual rows in a DataFrame
Source code in daft/dataframe/dataframe.py
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|
to_ray_dataset #
to_ray_dataset() -> DataSet
Converts the current DataFrame to a Ray Dataset which is useful for running distributed ML model training in Ray.
Returns:
Type | Description |
---|---|
DataSet | ray.data.dataset.DataSet: Ray dataset |
Note
This function can only work if Daft is running using the RayRunner
Source code in daft/dataframe/dataframe.py
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|
to_torch_iter_dataset #
to_torch_iter_dataset() -> IterableDataset
Convert the current DataFrame into a Torch IterableDataset <https://pytorch.org/docs/stable/data.html#torch.utils.data.IterableDataset>
__ for use with PyTorch.
Begins execution of the DataFrame if it is not yet executed.
Items will be returned in pydict format: a dict of {"column name": value}
for each row in the data.
Note
The produced dataset is meant to be used with the single-process DataLoader, and does not support data sharding hooks for multi-process data loading.
Do keep in mind that Daft is already using multithreading or multiprocessing under the hood to compute the data stream that feeds this dataset.
Tip
This method returns results locally. For distributed training, you may want to use DataFrame.to_ray_dataset().
Source code in daft/dataframe/dataframe.py
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|
to_torch_map_dataset #
to_torch_map_dataset() -> Dataset
Convert the current DataFrame into a map-style Torch Dataset for use with PyTorch.
This method will materialize the entire DataFrame and block on completion.
Items will be returned in pydict format: a dict of {"column name": value}
for each row in the data.
Note
If you do not need random access, you may get better performance out of an IterableDataset, which streams data items in as soon as they are ready and does not block on full materialization.
Tip
This method returns results locally. For distributed training, you may want to use DataFrame.to_ray_dataset().
Source code in daft/dataframe/dataframe.py
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|
transform #
Apply a function that takes and returns a DataFrame.
Allow splitting your transformation into different units of work (functions) while preserving the syntax for chaining transformations.
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 |
|
Parameters:
Name | Type | Description | Default |
---|---|---|---|
func | Callable[..., DataFrame] | A function that takes and returns a DataFrame. | required |
*args | Any | Positional arguments to pass to func. | () |
**kwargs | Any | Keyword arguments to pass to func. | {} |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Transformed DataFrame. |
Source code in daft/dataframe/dataframe.py
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|
union #
Returns the distinct union of two DataFrames.
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 |
|
Source code in daft/dataframe/dataframe.py
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|
union_all #
Returns the union of two DataFrames, including duplicates.
Examples:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
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Source code in daft/dataframe/dataframe.py
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union_all_by_name #
Returns the union of two DataFrames, including duplicates, with columns matched by name.
Examples:
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Source code in daft/dataframe/dataframe.py
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union_by_name #
Returns the distinct union by name.
Examples:
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Source code in daft/dataframe/dataframe.py
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unique #
unique() -> DataFrame
Computes distinct rows, dropping duplicates.
Alias for DataFrame.distinct.
Examples:
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Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame that has only distinct rows. |
Source code in daft/dataframe/dataframe.py
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unpivot #
unpivot(
ids: ManyColumnsInputType,
values: ManyColumnsInputType = [],
variable_name: str = "variable",
value_name: str = "value",
) -> DataFrame
Unpivots a DataFrame from wide to long format.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
ids | ManyColumnsInputType | Columns to keep as identifiers | required |
values | Optional[ManyColumnsInputType] | Columns to unpivot. If not specified, all columns except ids will be unpivoted. | [] |
variable_name | Optional[str] | Name of the variable column. Defaults to "variable". | 'variable' |
value_name | Optional[str] | Name of the value column. Defaults to "value". | 'value' |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Unpivoted DataFrame |
Tip
See also melt
Examples:
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Source code in daft/dataframe/dataframe.py
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where #
where(predicate: Union[Expression, str]) -> DataFrame
Filters rows via a predicate expression, similar to SQL WHERE
.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
predicate | Expression | expression that keeps row if evaluates to True. | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | Filtered DataFrame. |
Examples:
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You can also use a string expression as a predicate.
Note: this will use the method sql_expr
to parse the string into an expression this may raise an error if the expression is not yet supported in the sql engine.
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Source code in daft/dataframe/dataframe.py
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with_column #
with_column(
column_name: str, expr: Expression
) -> DataFrame
Adds a column to the current DataFrame with an Expression, equivalent to a select
with all current columns and the new one.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
column_name | str | name of new column | required |
expr | Expression | expression of the new column. | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with new column. |
Examples:
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Source code in daft/dataframe/dataframe.py
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with_column_renamed #
with_column_renamed(existing: str, new: str) -> DataFrame
Renames a column in the current DataFrame.
If the column in the DataFrame schema does not exist, this will be a no-op.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
existing | str | name of the existing column to rename | required |
new | str | new name for the column | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with the column renamed. |
Examples:
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Source code in daft/dataframe/dataframe.py
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with_columns #
with_columns(columns: Dict[str, Expression]) -> DataFrame
Adds columns to the current DataFrame with Expressions, equivalent to a select
with all current columns and the new ones.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
columns | Dict[str, Expression] | Dictionary of new columns in the format { name: expression } | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with new columns. |
Examples:
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Source code in daft/dataframe/dataframe.py
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with_columns_renamed #
with_columns_renamed(cols_map: Dict[str, str]) -> DataFrame
Renames multiple columns in the current DataFrame.
If the columns in the DataFrame schema do not exist, this will be a no-op.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
cols_map | Dict[str, str] | Dictionary of columns to rename in the format { existing: new } | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | DataFrame with the columns renamed. |
Examples:
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Source code in daft/dataframe/dataframe.py
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write_csv #
write_csv(
root_dir: Union[str, Path],
write_mode: Literal[
"append", "overwrite", "overwrite-partitions"
] = "append",
partition_cols: Optional[List[ColumnInputType]] = None,
io_config: Optional[IOConfig] = None,
) -> DataFrame
Writes the DataFrame as CSV files, returning a new DataFrame with paths to the files that were written.
Files will be written to <root_dir>/*
with randomly generated UUIDs as the file names.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
root_dir | str | root file path to write parquet files to. | required |
write_mode | str | Operation mode of the write. | 'append' |
partition_cols | Optional[List[ColumnInputType]] | How to subpartition each partition further. Defaults to None. | None |
io_config | Optional[IOConfig] | configurations to use when interacting with remote storage. | None |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | The filenames that were written out as strings. |
Note
This call is blocking and will execute the DataFrame when called
Source code in daft/dataframe/dataframe.py
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write_deltalake #
write_deltalake(
table: Union[
str,
Path,
DataCatalogTable,
DeltaTable,
UnityCatalogTable,
],
partition_cols: Optional[List[str]] = None,
mode: Literal[
"append", "overwrite", "error", "ignore"
] = "append",
schema_mode: Optional[
Literal["merge", "overwrite"]
] = None,
name: Optional[str] = None,
description: Optional[str] = None,
configuration: Optional[
Mapping[str, Optional[str]]
] = None,
custom_metadata: Optional[Dict[str, str]] = None,
dynamo_table_name: Optional[str] = None,
allow_unsafe_rename: bool = False,
io_config: Optional[IOConfig] = None,
) -> DataFrame
Writes the DataFrame to a Delta Lake table, returning a new DataFrame with the operations that occurred.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
table | Union[str, Path, DataCatalogTable, DeltaTable, UnityCatalogTable] | Destination Delta Lake Table or table URI to write dataframe to. | required |
partition_cols | List[str] | How to subpartition each partition further. If table exists, expected to match table's existing partitioning scheme, otherwise creates the table with specified partition columns. Defaults to None. | None |
mode | str | Operation mode of the write. | 'append' |
schema_mode | str | Schema mode of the write. If set to | None |
name | str | User-provided identifier for this table. | None |
description | str | User-provided description for this table. | None |
configuration | Mapping[str, Optional[str]] | A map containing configuration options for the metadata action. | None |
custom_metadata | Dict[str, str] | Custom metadata to add to the commit info. | None |
dynamo_table_name | str | Name of the DynamoDB table to be used as the locking provider if writing to S3. | None |
allow_unsafe_rename | bool | Whether to allow unsafe rename when writing to S3 or local disk. Defaults to False. | False |
io_config | IOConfig | configurations to use when interacting with remote storage. | None |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | The operations that occurred with this write. |
Note
This call is blocking and will execute the DataFrame when called
Source code in daft/dataframe/dataframe.py
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write_iceberg #
write_iceberg(
table: Table,
mode: str = "append",
io_config: Optional[IOConfig] = None,
) -> DataFrame
Writes the DataFrame to an Iceberg table, returning a new DataFrame with the operations that occurred.
Can be run in either append
or overwrite
mode which will either appends the rows in the DataFrame or will delete the existing rows and then append the DataFrame rows respectively.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
table | Table | Destination PyIceberg Table to write dataframe to. | required |
mode | str | Operation mode of the write. | 'append' |
io_config | IOConfig | A custom IOConfig to use when accessing Iceberg object storage data. If provided, configurations set in | None |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | The operations that occurred with this write. |
Note
This call is blocking and will execute the DataFrame when called
Source code in daft/dataframe/dataframe.py
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write_lance #
write_lance(
uri: Union[str, Path],
mode: Literal[
"create", "append", "overwrite"
] = "create",
io_config: Optional[IOConfig] = None,
**kwargs,
) -> DataFrame
Writes the DataFrame to a Lance table.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
uri | Union[str, Path] | The URI of the Lance table to write to | required |
mode | Literal['create', 'append', 'overwrite'] | The write mode. One of "create", "append", or "overwrite" | 'create' |
io_config | IOConfig | configurations to use when interacting with remote storage. | None |
**kwargs | Additional keyword arguments to pass to the Lance writer. | {} |
Note
write_lance` requires python 3.9 or higher
Examples:
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Source code in daft/dataframe/dataframe.py
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write_parquet #
write_parquet(
root_dir: Union[str, Path],
compression: str = "snappy",
write_mode: Literal[
"append", "overwrite", "overwrite-partitions"
] = "append",
partition_cols: Optional[List[ColumnInputType]] = None,
io_config: Optional[IOConfig] = None,
) -> DataFrame
Writes the DataFrame as parquet files, returning a new DataFrame with paths to the files that were written.
Files will be written to <root_dir>/*
with randomly generated UUIDs as the file names.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
root_dir | str | root file path to write parquet files to. | required |
compression | str | compression algorithm. Defaults to "snappy". | 'snappy' |
write_mode | str | Operation mode of the write. | 'append' |
partition_cols | Optional[List[ColumnInputType]] | How to subpartition each partition further. Defaults to None. | None |
io_config | Optional[IOConfig] | configurations to use when interacting with remote storage. | None |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | The filenames that were written out as strings. |
Note
This call is blocking and will execute the DataFrame when called
Source code in daft/dataframe/dataframe.py
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write_sink #
write_sink(sink: DataSink[T]) -> DataFrame
Writes the DataFrame to the given DataSink.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
sink | DataSink[T] | The DataSink to write to. | required |
Returns:
Name | Type | Description |
---|---|---|
DataFrame | DataFrame | A dataframe from the micropartition returned by the DataSink's |
Source code in daft/dataframe/dataframe.py
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