polars.Expr.str.contains#

Expr.str.contains(pattern: str | Expr, literal: bool = False, strict: bool = True) → Expr[source]#

Check if string contains a substring that matches a regex.

Parameters:

pattern: A valid regex pattern.
literal: Treat pattern as a literal string.
strict: Raise an error if the underlying pattern is not a valid regex expression, otherwise mask out with a null value.

See also

starts_with: Check if string values start with a substring.
ends_with: Check if string values end with a substring.

Examples

>>> df = pl.DataFrame({"a": ["Crab", "cat and dog", "rab$bit", None]})
>>> df.select(
...     [
...         pl.col("a"),
...         pl.col("a").str.contains("cat|bit").alias("regex"),
...         pl.col("a").str.contains("rab$", literal=True).alias("literal"),
...     ]
... )
shape: (4, 3)
┌─────────────┬───────┬─────────┐
│ a           ┆ regex ┆ literal │
│ ---         ┆ ---   ┆ ---     │
│ str         ┆ bool  ┆ bool    │
╞═════════════╪═══════╪═════════╡
│ Crab        ┆ false ┆ false   │
│ cat and dog ┆ true  ┆ false   │
│ rab$bit     ┆ true  ┆ true    │
│ null        ┆ null  ┆ null    │
└─────────────┴───────┴─────────┘