Join lists contained as elements in the Series/Index with passed delimiter.
If the elements of a Series are lists themselves, join the content of these lists using the delimiter passed to the function. This function is an equivalent to str.join().
Delimiter to use between list entries.
The list entries concatenated by intervening occurrences of the delimiter.
If the supplied Series contains neither strings nor lists.
See also
str.joinStandard library version of this method.
Series.str.splitSplit strings around given separator/delimiter.
Notes
If any of the list items is not a string object, the result of the join will be NaN.
Examples
Example with a list that contains non-string elements.
>>> s = pd.Series([['lion', 'elephant', 'zebra'],
... [1.1, 2.2, 3.3],
... ['cat', np.nan, 'dog'],
... ['cow', 4.5, 'goat'],
... ['duck', ['swan', 'fish'], 'guppy']])
>>> s
0 [lion, elephant, zebra]
1 [1.1, 2.2, 3.3]
2 [cat, nan, dog]
3 [cow, 4.5, goat]
4 [duck, [swan, fish], guppy]
dtype: object
Join all lists using a ‘-’. The lists containing object(s) of types other than str will produce a NaN.
>>> s.str.join('-')
0 lion-elephant-zebra
1 NaN
2 NaN
3 NaN
4 NaN
dtype: object
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https://pandas.pydata.org/pandas-docs/version/2.3.0/reference/api/pandas.Series.str.join.html