polars.Expr.str.join

Expr.str.join(delimiter: str = '', *, ignore_nulls: bool = True) → Expr

Vertically concatenate the string values in the column 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. This means that if the column contains any null values, the output is null.

Returns:

Expr

Expression of data type String.

Examples

>>> df = pl.DataFrame({"foo": [1, None, 3]})
>>> df.select(pl.col("foo").str.join("-"))
shape: (1, 1)
┌─────┐
│ foo │
│ --- │
│ str │
╞═════╡
│ 1-3 │
└─────┘
>>> df.select(pl.col("foo").str.join(ignore_nulls=False))
shape: (1, 1)
┌──────┐
│ foo  │
│ ---  │
│ str  │
╞══════╡
│ null │
└──────┘