class_docstr: Namespace for expressions on a meta level.
class_docstr_tok: ["Namespace","for","expressions","on","a","meta","level","."]
docstr: Get the column name that this expression would produce.
  
  It may not always be possible to determine the output name as that can depend
  on the schema of the context; in that case this will raise `ComputeError` if
  `raise_if_undetermined` is True (the default), or `None` otherwise.
  
  Examples
  --------
  >>> e = pl.col("foo") * pl.col("bar")
  >>> e.meta.output_name()
  'foo'
  >>> e_filter = pl.col("foo").filter(pl.col("bar") == 13)
  >>> e_filter.meta.output_name()
  'foo'
  >>> e_sum_over = pl.sum("foo").over("groups")
  >>> e_sum_over.meta.output_name()
  'foo'
  >>> e_sum_slice = pl.sum("foo").slice(pl.count() - 10, pl.col("bar"))
  >>> e_sum_slice.meta.output_name()
  'foo'
  >>> pl.count().meta.output_name()
  'count'
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code: def output_name(
      self, *, raise_if_undetermined: bool = True
  ) -> str | None:
      """
      Get the column name that this expression would produce.
  
      It may not always be possible to determine the output name as that can depend
      on the schema of the context; in that case this will raise `ComputeError` if
      `raise_if_undetermined` is True (the default), or `None` otherwise.
  
      Examples
      --------
      >>> e = pl.col("foo") * pl.col("bar")
      >>> e.meta.output_name()
      'foo'
      >>> e_filter = pl.col("foo").filter(pl.col("bar") == 13)
      >>> e_filter.meta.output_name()
      'foo'
      >>> e_sum_over = pl.sum("foo").over("groups")
      >>> e_sum_over.meta.output_name()
      'foo'
      >>> e_sum_slice = pl.sum("foo").slice(pl.count() - 10, pl.col("bar"))
      >>> e_sum_slice.meta.output_name()
      'foo'
      >>> pl.count().meta.output_name()
      'count'
  
      """
      try:
          return self._pyexpr.meta_output_name()
      except ComputeError:
          if not raise_if_undetermined:
              return None
          raise
  
imports: from __future__ import annotations
  from io import BytesIO, StringIO
  from pathlib import Path
  from typing import TYPE_CHECKING, Literal, overload
  from polars.exceptions import ComputeError
  from polars.utils._wrap import wrap_expr
  from polars.utils.deprecation import deprecate_nonkeyword_arguments
  from polars.utils.various import normalize_filepath
label_desc: Use image node_id 11 for calling the ExprMetaNameSpace obj's underlying member method code with example usage: obj.output_name() and returns: self, None