bnm3k / polars-fuzzy-match

Polars extension for fzf-style fuzzy matching
MIT License
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polars polars-dataframe python rust

Polars Fuzzy Matching

Installation

pip install polars
pip install polars-fuzzy-match

Usage

With both the plugin and polars installed, usage is as follows:

import polars as pl
from polars_fuzzy_match import fuzzy_match_score

df = pl.DataFrame(
    {
        'strs': ['foo', 'foo quz BAR', 'baaarfoo', 'quz'],
    }
)
pattern = 'bar'
out = df.with_columns(
    score=fuzzy_match_score(
        pl.col('strs'),
        pattern,
    )
)
print(out)

This outputs:

shape: (4, 2)
┌─────────────┬───────┐
│ strs        ┆ score │
│ ---         ┆ ---   │
│ str         ┆ u32   │
╞═════════════╪═══════╡
│ foo         ┆ null  │
│ foo quz BAR ┆ 88    │
│ baaarfoo    ┆ 74    │
│ quz         ┆ null  │
└─────────────┴───────┘

When there is no match, score is null. When the pattern matches the value in the given column, score is non-null. The higher the score, the closer the value is to the pattern. Therefore, we can filter out values that do not match and order by score:

pattern = 'bar'
out = (
    df.with_columns(
        score=fuzzy_match_score(
            pl.col('strs'),
            pattern,
        )
    )
    .filter(pl.col('score').is_not_null())
    .sort(by='score', descending=True)
)
print(out)

This outputs:

shape: (2, 2)
┌─────────────┬───────┐
│ strs        ┆ score │
│ ---         ┆ ---   │
│ str         ┆ u32   │
╞═════════════╪═══════╡
│ foo quz BAR ┆ 88    │
│ baaarfoo    ┆ 74    │
└─────────────┴───────┘

Fzf-style search syntax

This plugin supports Fzf-style search syntax for the pattern. It's worth noting that this section is taken almost verbatim from the Fzf README:

Pattern Match type Description
bar fuzzy items that fuzzy match bar e.g. 'bXXaXXr'
'foo substring exact match items that include foo e.g. 'is foo ok'
^music prefix exact match items that start with music
.mp3$ suffix exact match items that end with .mp3
!fire inverse exact match items that do not include fire
!^music inverse prefix exact match items that do not start with music
!.mp3$ inverse suffix exact match items that do not end with .mp3

Credits

  1. Marco Gorelli's Tutorial on writing Polars Plugin. See here.
  2. The Helix Editor team for the Nucleo fuzzy matching library.