cudf.core.column.lists.ListMethods.index#

ListMethods.index(search_key: ScalarLike | ColumnLike) → ParentType[source]#

Returns integers representing the index of the search key for each row.

If search_key is a sequence, it must be the same length as the Series and search_key[i] represents the search key for the i-th row of the Series.

If the search key is not contained in a row, -1 is returned. If either the row or the search key are null, <NA> is returned. If the search key is contained multiple times, the smallest matching index is returned.

Parameters:

search_keyscalar or sequence of scalars: Element or elements being searched for in each row of the list column

Returns:

Series or Index

Examples

>>> s = cudf.Series([[1, 2, 3], [3, 4, 5], [4, 5, 6]])
>>> s.list.index(4)
0   -1
1    1
2    0
dtype: int32

>>> s = cudf.Series([["a", "b", "c"], ["x", "y", "z"]])
>>> s.list.index(["b", "z"])
0    1
1    2
dtype: int32

>>> s = cudf.Series([[4, 5, 6], None, [-3, -2, -1]])
>>> s.list.index([None, 3, -2])
0    <NA>
1    <NA>
2       1
dtype: int32