Merge pull request #123 from brentomagic/unique

unique()

narwhals/series.py

@@ -230,6 +230,40 @@ def cum_sum(self) -> Self:
         return self._from_series(self._series.cum_sum())
 
     def unique(self) -> Self:
+        """
+        Returns unique values
+
+        Examples:
+            >>> import pandas as pd
+            >>> import polars as pl
+            >>> import narwhals as nw
+            >>> s = [2, 4, 4, 6]
+            >>> s_pd = pd.Series(s)
+            >>> s_pl = pl.Series(s)
+
+            Let's define a dataframe-agnostic function:
+
+            >>> def func(s_any):
+            ...    s = nw.from_native(s_any, series_only=True)
+            ...    s = s.unique()
+            ...    return nw.to_native(s)
+
+            We can then pass either pandas or Polars to `func`:
+
+            >>> func(s_pd)
+            0    2
+            1    4
+            2    6
+            dtype: int64
+            >>> func(s_pl)  # doctest: +NORMALIZE_WHITESPACE
+            shape: (3,)
+            Series: '' [i64]
+            [
+               2
+               4
+               6
+            ]
+        """
         return self._from_series(self._series.unique())
 
     def diff(self) -> Self: