How to create dummies from list with multiple values and predefined categories? [duplicate]

Question

I'd like to transform this :

In [4]: df
Out[4]:
      label
0     (a, e)
1     (a, d)
2       (b,)
3     (d, e)

to This :

   a  b  c  d  e
0  1  0  0  0  1
1  1  0  0  1  0
2  0  1  0  0  0
3  0  0  0  1  1

As you can see there are predefined columns, 'a', 'b', 'c', 'd', 'e' and c is empty but still exists.

I tried multiple things like this : df.str.join('|').str.get_dummies() first without all the columns just to get the dummies with multiple values in the input but I want to add the predefined columns thing to it.

Thank you for your help !

Answer 1

Good practice for sklearn

from sklearn.preprocessing import MultiLabelBinarizer

mlb = MultiLabelBinarizer()

print (pd.DataFrame(mlb.fit_transform(df['label']),columns=mlb.classes_, index=df.index))

Answer 2

Create a new DataFrame, then stack + get_dummies. any along the original index for the dummies.

pd.get_dummies(pd.DataFrame([*df.label], index=df.index).stack()).any(level=0).astype(int)

   a  b  d  e
0  1  0  0  1
1  1  0  1  0
2  0  1  0  0
3  0  0  1  1

---

Because you have pre-defined columns, we can reindex and fill missing with 0.

res = pd.get_dummies(pd.DataFrame([*df.label], index=df.index).stack()).any(level=0)
res = res.reindex(list('abcde'), axis=1).fillna(0).astype(int)

#   a  b  c  d  e
#0  1  0  0  0  1
#1  1  0  0  1  0
#2  0  1  0  0  0
#3  0  0  0  1  1