pandas.core.reshape.get_dummies

pandas.core.reshape.get_dummies(data, prefix=None, prefix_sep='_', dummy_na=False, columns=None)

Convert categorical variable into dummy/indicator variables

Parameters :

data : array-like, Series, or DataFrame

prefix : string, list of strings, or dict of strings, default None

String to append DataFrame column names Pass a list with length equal to the number of columns when calling get_dummies on a DataFrame. Alternativly, prefix can be a dictionary mapping column names to prefixes.

prefix_sep : string, default ‘_’

If appending prefix, separator/delimiter to use. Or pass a list or dictionary as with prefix.

dummy_na : bool, default False

Add a column to indicate NaNs, if False NaNs are ignored.

columns : list-like, default None

Column names in the DataFrame to be encoded. If columns is None then all the columns with object or category dtype will be converted.

Returns :

dummies : DataFrame

Examples

>>> import pandas as pd
>>> s = pd.Series(list('abca'))

>>> get_dummies(s)
   a  b  c
0  1  0  0
1  0  1  0
2  0  0  1
3  1  0  0

>>> s1 = ['a', 'b', np.nan]

>>> get_dummies(s1)
   a  b
0  1  0
1  0  1
2  0  0

>>> get_dummies(s1, dummy_na=True)
   a  b  NaN
0  1  0    0
1  0  1    0
2  0  0    1

>>> df = DataFrame({'A': ['a', 'b', 'a'], 'B': ['b', 'a', 'c'],
                    'C': [1, 2, 3]})

>>> get_dummies(df, prefix=['col1', 'col2']):
   C  col1_a  col1_b  col2_a  col2_b  col2_c
0  1       1       0       0       1       0
1  2       0       1       1       0       0
2  3       1       0       0       0       1

See also Series.str.get_dummies.