class_docstr: Namespace for string related expressions.
class_docstr_tok: ["Namespace","for","string","related","expressions","."]
docstr: Vertically concat the values in the Series to a single string value.
  
  Parameters
  ----------
  delimiter
      The delimiter to insert between consecutive string values.
  ignore_nulls
      Ignore null values (default).
  
      If set to ``False``, null values will be propagated.
      if the column contains any null values, the output is ``None``.
  
  Returns
  -------
  Expr
      Expression of data type :class:`String`.
  
  Examples
  --------
  >>> df = pl.DataFrame({"foo": [1, None, 2]})
  >>> df.select(pl.col("foo").str.concat("-"))
  shape: (1, 1)
  ┌─────┐
  │ foo │
  │ --- │
  │ str │
  ╞═════╡
  │ 1-2 │
  └─────┘
  >>> df = pl.DataFrame({"foo": [1, None, 2]})
  >>> df.select(pl.col("foo").str.concat("-", ignore_nulls=False))
  shape: (1, 1)
  ┌──────┐
  │ foo  │
  │ ---  │
  │ str  │
  ╞══════╡
  │ null │
  └──────┘
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code: def concat(
      self, delimiter: str = "-", *, ignore_nulls: bool = True
  ) -> Expr:
      """
      Vertically concat the values in the Series to a single string value.
  
      Parameters
      ----------
      delimiter
          The delimiter to insert between consecutive string values.
      ignore_nulls
          Ignore null values (default).
  
          If set to ``False``, null values will be propagated.
          if the column contains any null values, the output is ``None``.
  
      Returns
      -------
      Expr
          Expression of data type :class:`String`.
  
      Examples
      --------
      >>> df = pl.DataFrame({"foo": [1, None, 2]})
      >>> df.select(pl.col("foo").str.concat("-"))
      shape: (1, 1)
      ┌─────┐
      │ foo │
      │ --- │
      │ str │
      ╞═════╡
      │ 1-2 │
      └─────┘
      >>> df = pl.DataFrame({"foo": [1, None, 2]})
      >>> df.select(pl.col("foo").str.concat("-", ignore_nulls=False))
      shape: (1, 1)
      ┌──────┐
      │ foo  │
      │ ---  │
      │ str  │
      ╞══════╡
      │ null │
      └──────┘
  
      """
      return wrap_expr(self._pyexpr.str_concat(delimiter, ignore_nulls))
  
imports: from __future__ import annotations
  import warnings
  from typing import TYPE_CHECKING
  import polars._reexport
  from polars import functions
  from polars.datatypes import Date, Datetime, Int32, Time, py_type_to_dtype
  from polars.exceptions import ChronoFormatWarning
  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, rename_use_earliest_to_ambiguous
  from polars.utils.various import find_stacklevel
label_desc: Use image node_id 9 for calling the ExprStringNameSpace obj's underlying member method code with example usage: obj.concat(delimiter) and returns: wrap_expr