class_docstr: Namespace for list related expressions.
class_docstr_tok: ["Namespace","for","list","related","expressions","."]
docstr: Count how often the value produced by `element` occurs.
  
  Parameters
  ----------
  element
      An expression that produces a single value
  
  Examples
  --------
  >>> df = pl.DataFrame({"a": [[0], [1], [1, 2, 3, 2], [1, 2, 1], [4, 4]]})
  >>> df.with_columns(number_of_twos=pl.col("a").list.count_matches(2))
  shape: (5, 2)
  ┌─────────────┬────────────────┐
  │ a           ┆ number_of_twos │
  │ ---         ┆ ---            │
  │ list[i64]   ┆ u32            │
  ╞═════════════╪════════════════╡
  │ [0]         ┆ 0              │
  │ [1]         ┆ 0              │
  │ [1, 2, … 2] ┆ 2              │
  │ [1, 2, 1]   ┆ 1              │
  │ [4, 4]      ┆ 0              │
  └─────────────┴────────────────┘
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code: def count_matches(self, element: IntoExpr) -> Expr:
      """
      Count how often the value produced by `element` occurs.
  
      Parameters
      ----------
      element
          An expression that produces a single value
  
      Examples
      --------
      >>> df = pl.DataFrame({"a": [[0], [1], [1, 2, 3, 2], [1, 2, 1], [4, 4]]})
      >>> df.with_columns(number_of_twos=pl.col("a").list.count_matches(2))
      shape: (5, 2)
      ┌─────────────┬────────────────┐
      │ a           ┆ number_of_twos │
      │ ---         ┆ ---            │
      │ list[i64]   ┆ u32            │
      ╞═════════════╪════════════════╡
      │ [0]         ┆ 0              │
      │ [1]         ┆ 0              │
      │ [1, 2, … 2] ┆ 2              │
      │ [1, 2, 1]   ┆ 1              │
      │ [4, 4]      ┆ 0              │
      └─────────────┴────────────────┘
  
      """
      element = parse_as_expression(element, str_as_lit=True)
      return wrap_expr(self._pyexpr.list_count_matches(element))
  
imports: from __future__ import annotations
  import copy
  from typing import TYPE_CHECKING, Any, Callable, Sequence
  import polars._reexport
  from polars import functions
  from polars.utils._parse_expr_input import parse_as_expression
  from polars.utils._wrap import wrap_expr
  from polars.utils.deprecation import deprecate_renamed_function, deprecate_renamed_parameter
label_desc: Use image node_id 30 for calling the ExprListNameSpace obj's underlying member method code with example usage: obj.count_matches(element) and returns: wrap_expr