polars.Expr.str.pad_start#

Expr.str.pad_start(length: int, fill_char: str = ' ') → Expr[source]#

Pad the start of the string until it reaches the given length.

Parameters:

length: Pad the string until it reaches this length. Strings with length equal to or greater than this value are returned as-is.
fill_char: The character to pad the string with.

See also

pad_end
zfill

Examples

>>> df = pl.DataFrame({"a": ["cow", "monkey", "hippopotamus", None]})
>>> df.with_columns(padded=pl.col("a").str.pad_start(8, "*"))
shape: (4, 2)
┌──────────────┬──────────────┐
│ a            ┆ padded       │
│ ---          ┆ ---          │
│ str          ┆ str          │
╞══════════════╪══════════════╡
│ cow          ┆ *****cow     │
│ monkey       ┆ **monkey     │
│ hippopotamus ┆ hippopotamus │
│ null         ┆ null         │
└──────────────┴──────────────┘