pandas (original) (raw)

Code Sample, a copy-pastable example if possible

In [2]: pd.Series(index=range(10))[{1:2,3:4}] Out[2]: 1 NaN 3 NaN dtype: float64

In [3]: pd.Series(index=range(10))[{1:2,3:4}.keys()] Out[3]: 1 NaN 3 NaN dtype: float64

In [4]: pd.DataFrame(index=range(10), columns=range(10))[{1:2,3:4}]

TypeError Traceback (most recent call last) in () ----> 1 pd.DataFrame(index=range(10), columns=range(10))[{1:2,3:4}]

~/nobackup/repo/pandas/pandas/core/frame.py in getitem(self, key) 2683 return self._getitem_multilevel(key) 2684 else: -> 2685 return self._getitem_column(key) 2686 2687 def _getitem_column(self, key):

~/nobackup/repo/pandas/pandas/core/frame.py in _getitem_column(self, key) 2690 # get column 2691 if self.columns.is_unique: -> 2692 return self._get_item_cache(key) 2693 2694 # duplicate columns & possible reduce dimensionality

~/nobackup/repo/pandas/pandas/core/generic.py in _get_item_cache(self, item) 2482 """Return the cached item, item represents a label indexer.""" 2483 cache = self._item_cache -> 2484 res = cache.get(item) 2485 if res is None: 2486 values = self._data.get(item)

TypeError: unhashable type: 'dict'

In [5]: pd.DataFrame(index=range(10), columns=range(10))[{1:2,3:4}.keys()]

TypeError Traceback (most recent call last) in () ----> 1 pd.DataFrame(index=range(10), columns=range(10))[{1:2,3:4}.keys()]

TypeError: unhashable type: 'dict_keys'

Problem description

I know that DataFrame.__getitem__ is a mess ( #9595 ), but I don't see why dicts and dict keys shouldn't be just considered list-likes as it happens with Series.

Expected Output

In [6]: pd.DataFrame(index=range(10), columns=range(10))[list({1:2,3:4})] Out[6]: 1 3 0 NaN NaN 1 NaN NaN 2 NaN NaN 3 NaN NaN 4 NaN NaN 5 NaN NaN 6 NaN NaN 7 NaN NaN 8 NaN NaN 9 NaN NaN

Output of `pd.show_versions()`

INSTALLED VERSIONS

commit: None
python: 3.5.3.final.0
python-bits: 64
OS: Linux
OS-release: 4.9.0-6-amd64
machine: x86_64
processor:
byteorder: little
LC_ALL: None
LANG: it_IT.UTF-8
LOCALE: it_IT.UTF-8

pandas: 0.24.0.dev0+25.gcd0447102
pytest: 3.5.0
pip: 9.0.1
setuptools: 39.2.0
Cython: 0.25.2
numpy: 1.14.3
scipy: 0.19.0
pyarrow: None
xarray: None
IPython: 6.2.1
sphinx: 1.5.6
patsy: 0.5.0
dateutil: 2.7.3
pytz: 2018.4
blosc: None
bottleneck: 1.2.0dev
tables: 3.3.0
numexpr: 2.6.1
feather: 0.3.1
matplotlib: 2.2.2.post1153+gff6786446
openpyxl: 2.3.0
xlrd: 1.0.0
xlwt: 1.3.0
xlsxwriter: 0.9.6
lxml: 4.1.1
bs4: 4.5.3
html5lib: 0.999999999
sqlalchemy: 1.0.15
pymysql: None
psycopg2: None
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: 0.2.1