Series.map(m: Mapping) can fail with "object is not callable" #29733
Description
Code Sample, a copy-pastable example if possible
import pandas as pd from collections import UserDict, Counter class MissingDict(UserDict): def __missing__(self, key): return key s = pd.Series(list("aab")) s.map(Counter({"a": 1})) # 0 1 # 1 1 # 2 0 # dtype: int64 s.map(MissingDict({"a": "c"})) # <ipython-input-48-6cd4b0d364c9> in <module> # ----> 1 s.map(MissingDict({"a": "c"})) # /usr/local/lib/python3.7/site-packages/pandas/core/series.py in map(self, arg, na_action) # 3826 dtype: object # 3827 """ # -> 3828 new_values = super()._map_values(arg, na_action=na_action) # 3829 return self._constructor(new_values, index=self.index).__finalize__(self) # 3830 # /usr/local/lib/python3.7/site-packages/pandas/core/base.py in _map_values(self, mapper, na_action) # 1298 # 1299 # mapper is a function # -> 1300 new_values = map_f(values, mapper) # 1301 # 1302 return new_values # pandas/_libs/lib.pyx in pandas._libs.lib.map_infer() # TypeError: 'MissingDict' object is not callableProblem description
Series.map can sometimes take Mapping subclasses other than dict, but not always. I think it would make sense if any object that satisfied isinstance(x, collections.abc.Mapping) could be used as a mapping. I came across this while trying to use map where I only wanted values present as keys in the mapping to change (I went for s.map(lambda x: {"a": "b"}.get(x, x)) as a workaround).
collections.Counter and collections.defaultdict work fine, which made me expect other Mappings would as well.
Expected Output
I expected s.map(MissingDict({"a": "c"})) to do something like:
s.map(lambda x: MissingDict({"a": "c"})[x]) # 0 c # 1 c # 2 b # dtype: objectOutput of pd.show_versions()
INSTALLED VERSIONS ------------------ commit : None python : 3.7.4.final.0 python-bits : 64 OS : Darwin OS-release : 18.7.0 machine : x86_64 processor : i386 byteorder : little LC_ALL : None LANG : en_US.UTF-8 LOCALE : en_US.UTF-8 pandas : 0.25.3 numpy : 1.17.4 pytz : 2018.9 dateutil : 2.7.5 pip : 19.3.1 setuptools : 41.6.0 Cython : 0.29.14 pytest : 5.2.2 hypothesis : 4.44.1 sphinx : 2.2.1 blosc : None feather : None xlsxwriter : None lxml.etree : 4.4.1 html5lib : 1.0.1 pymysql : None psycopg2 : None jinja2 : 2.10.1 IPython : 7.9.0 pandas_datareader: None bs4 : 4.8.1 bottleneck : None fastparquet : 0.3.2 gcsfs : None lxml.etree : 4.4.1 matplotlib : 3.0.3 numexpr : 2.7.0 odfpy : None openpyxl : 2.6.2 pandas_gbq : None pyarrow : 0.15.1 pytables : None s3fs : None scipy : 1.3.2 sqlalchemy : None tables : 3.6.1 xarray : 0.14.0 xlrd : 1.2.0 xlwt : None xlsxwriter : None