CODEWITHSUNDEEP
pythonpandasmatrix
C_psy
C_psy

Reputation: 647

Retain order of values in binary matrix in Python

I created a binary matrix from 2 pandas columns

df:

ID_2  ID_1
1111  1
22222 2
33333 3
33333 4
44444 5
55555 6
55555 7
66666 8
66666 9
77777 10
77777 11
77777 12

Using:

A = pd.get_dummies(df.set_index('ID_1')['ID_2'].astype(str)).max(level=0)
print (A)

This creates a matrix:

      22222 33333 44444 55555 66666 77777 11111
ID_2
1     0     0     0     0     0     0     1
2     1     0     0     0     0     0     0
3     0     1     0     0     0     0     0
4     0     1     0     0     0     0     0
5     0     0     1     0     0     0     0

....

all fine - except the first unique value from ID_1 is placed in the last column. I need the order of the values to be to be retained as in ID_2.

Upvotes: 1

Views: 68

Answers (1)

Joe
Joe

Reputation: 12417

If you want to reorder the columns, I think you need this:

A = A.reindex_axis(['11111'] + list(A.columns[:-1]), axis=1)

Edit

You can do in this way:

 from collections import OrderedDict
 cols = list(OrderedDict.fromkeys(list(df['ID_2'].values)))
 cols = [str(i) for i in cols]
 A = A.reindex_axis(cols, axis=1)

here you keep the element of the column in a ordered way(and without duplicates) and then you use them as header

Upvotes: 1

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