【pandas】[3] DataFrame通过数据类型选择子数据框

DataFrame.select_dtypes(include=None, exclude=None)

Return a subset of the DataFrame’s columns based on the column dtypes.

Parameters:	include, exclude : scalar or list-like A selection of dtypes or strings to be included/excluded. At least one of these parameters must be supplied.
Returns:	subset : DataFrame The subset of the frame including the dtypes in include and excluding the dtypes in exclude.
Raises:	ValueError If both of include and exclude are empty If include and exclude have overlapping elements If any kind of string dtype is passed in.

Notes

• To select all numeric types, use np.number or 'number'
• To select strings you must use the object dtype, but note that this will return all object dtype columns
• See the numpy dtype hierarchy
• To select datetimes, use np.datetime64, 'datetime' or 'datetime64'
• To select timedeltas, use np.timedelta64, 'timedelta' or 'timedelta64'
• To select Pandas categorical dtypes, use 'category'
• To select Pandas datetimetz dtypes, use 'datetimetz' (new in 0.20.0) or 'datetime64[ns, tz]'

Examples

>>> df = pd.DataFrame({'a': [1, 2] * 3,
...                    'b': [True, False] * 3,
...                    'c': [1.0, 2.0] * 3})
>>> df
        a      b  c
0       1   True  1.0
1       2  False  2.0
2       1   True  1.0
3       2  False  2.0
4       1   True  1.0
5       2  False  2.0

>>> df.select_dtypes(include='bool')
   b
0  True
1  False
2  True
3  False
4  True
5  False

>>> df.select_dtypes(include=['float64'])
   c
0  1.0
1  2.0
2  1.0
3  2.0
4  1.0
5  2.0

>>> df.select_dtypes(exclude=['int'])
       b    c
0   True  1.0
1  False  2.0
2   True  1.0
3  False  2.0
4   True  1.0
5  False  2.0