pandas_select.column.AllStr

class AllStr(*, strict=False)

Select columns with dtype object, and string if pandas version >= 1.0.0.

Parameters

strict (default False) – If True, filter out object dtypes.

Raises

ValueError – If pandas version < 1.0.0 and strict = True

Notes

Be aware that strict=False, the default, will select all object dtype columns. Columns with mixed types are stored with the object dtype!

See also

HasDtype, AllNominal

Examples

>>> df = pd.DataFrame({"i": [1, 2],
...                    "o": ["a", 2],
...                    "obj_str": ["a", "b"],
...                    "str": ["a", "b"]})
>>> try:
...     df = df.astype({"obj_str": "object", "str": "string"})
... except TypeError: # pandas.__version__ < '1.0.0'
...     df = df.astype({"obj_str": "object", "str": "object"})
>>> df
   i  o obj_str str
0  1  a       a   a
1  2  2       b   b
>>> df[AllStr()]
   o obj_str str
0  a       a   a
1  2       b   b
>>> pd.__version__ >= '1.0.0'
True
>>> df[AllStr(strict=True)]
  str
0   a
1   b