pyarrow.Schema¶

class pyarrow.Schema¶

Bases: pyarrow.lib._Weakrefable

__init__(*args, **kwargs)¶

Methods

`__init__`(args, *kwargs)
`add_metadata`(self, metadata)
`append`(self, Field field)	Append a field at the end of the schema.
`empty_table`(self)	Provide an empty table according to the schema.
`equals`(self, Schema other, ...)	Test if this schema is equal to the other
`field`(self, i)	Select a field by its column name or numeric index.
`field_by_name`(self, name)	Access a field by its name rather than the column index.
`from_pandas`(type cls, df[, preserve_index])	Returns implied schema from dataframe
`get_all_field_indices`(self, name)	Return sorted list of indices for fields with the given name
`get_field_index`(self, name)	Return index of field with given unique name.
`insert`(self, int i, Field field)	Add a field at position i to the schema.
`remove`(self, int i)	Remove the field at index i from the schema.
`remove_metadata`(self)	Create new schema without metadata, if any
`serialize`(self[, memory_pool])	Write Schema to Buffer as encapsulated IPC message
`set`(self, int i, Field field)	Replace a field at position i in the schema.
`to_string`(self[, truncate_metadata, ...])	Return human-readable representation of Schema
`with_metadata`(self, metadata)	Add metadata as dict of string keys and values to Schema

Attributes

`metadata`
`names`	The schema's field names.
`pandas_metadata`	Return deserialized-from-JSON pandas metadata field (if it exists)
`types`	The schema's field types.

add_metadata(self, metadata)¶

append(self, Field field)¶

Append a field at the end of the schema.

In contrast to Python’s list.append() it does return a new object, leaving the original Schema unmodified.

Parameters

field: Field

Returns

schema: Schema: New object with appended field.

empty_table(self)¶

Provide an empty table according to the schema.

Returns

table: pyarrow.Table

equals(self, Schema other, bool check_metadata=False)¶

Test if this schema is equal to the other

Parameters

otherpyarrow.Schema
check_metadatabool, default False: Key/value metadata must be equal too

Returns

is_equalbool

field(self, i)¶

Select a field by its column name or numeric index.

Parameters

iint or str

Returns

pyarrow.Field

field_by_name(self, name)¶

Access a field by its name rather than the column index.

Parameters

name: str

Returns

field: pyarrow.Field

from_pandas(type cls, df, preserve_index=None)¶

Returns implied schema from dataframe

Parameters

dfpandas.DataFrame
preserve_indexbool, default True: Whether to store the index as an additional column (or columns, for MultiIndex) in the resulting Table. The default of None will store the index as a column, except for RangeIndex which is stored as metadata only. Use preserve_index=True to force it to be stored as a column.

Returns

pyarrow.Schema

Examples

>>> import pandas as pd
>>> import pyarrow as pa
>>> df = pd.DataFrame({
    ...     'int': [1, 2],
    ...     'str': ['a', 'b']
    ... })
>>> pa.Schema.from_pandas(df)
int: int64
str: string
__index_level_0__: int64

get_all_field_indices(self, name)¶: Return sorted list of indices for fields with the given name

get_field_index(self, name)¶: Return index of field with given unique name. Returns -1 if not found or if duplicated

insert(self, int i, Field field)¶

Add a field at position i to the schema.

Parameters

i: int
field: Field

Returns

schema: Schema

metadata¶

names¶

The schema’s field names.

Returns

list of str

pandas_metadata¶: Return deserialized-from-JSON pandas metadata field (if it exists)

remove(self, int i)¶

Remove the field at index i from the schema.

Parameters

i: int

Returns

schema: Schema

remove_metadata(self)¶

Create new schema without metadata, if any

Returns

schemapyarrow.Schema

serialize(self, memory_pool=None)¶

Write Schema to Buffer as encapsulated IPC message

Parameters

memory_poolMemoryPool, default None: Uses default memory pool if not specified

Returns

serializedBuffer

set(self, int i, Field field)¶

Replace a field at position i in the schema.

Parameters

i: int
field: Field

Returns

schema: Schema

to_string(self, truncate_metadata=True, show_field_metadata=True, show_schema_metadata=True)¶

Return human-readable representation of Schema

Parameters

truncate_metadatabool, default True: Limit metadata key/value display to a single line of ~80 characters or less
show_field_metadatabool, default True: Display Field-level KeyValueMetadata
show_schema_metadatabool, default True: Display Schema-level KeyValueMetadata

Returns

strthe formatted output

types¶

The schema’s field types.

Returns

list of DataType

with_metadata(self, metadata)¶

Add metadata as dict of string keys and values to Schema

Parameters

metadatadict: Keys and values must be string-like / coercible to bytes

Returns

schemapyarrow.Schema

pyarrow.Field

pyarrow.ExtensionType