Create a dummy based on other variables in Python

Question

I have three columns dummy variables, 'dummy1', 'dummy2' and 'dummy3. I would like to create a new column with a new dummy, 'new_dummy', with 1 if at least one of dummies of before has a value 1. I am using python.

I have in mind something like this:

mydata['new_dummy'] = mydata.apply(lambda x: x['1'] if x['dummy1'] or x['dummy2'] or x['dummy3'] == '1' else x['0'], axis=1)

But it does not work. Give me an error saying "KeyError: '0'". Any idea why I have that error or any other method to do it?

Sachin Kohli · Accepted Answer · 2022-09-25 15:01:40Z

1

Try This...

mydata = pd.DataFrame({"dummy1":["1","0"],
                       "dummy2":["0","0"],
                       "dummy3":["0","0"]})

mydata['new_dummy'] = mydata.apply(lambda x: '1' if str(x['dummy1']) == '1' or str(x['dummy2']) == '1' or str(x['dummy3']) == '1' else '0', axis=1)

# Output...

  dummy1 dummy2 dummy3 new_dummy
0      1      0      0         1
1      0      0      0         0

edited Sep 25, 2022 at 15:01

answered Sep 25, 2022 at 14:29

Sachin Kohli

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3 Comments

OgeiD Over a year ago

Thank for your comment but it does not work. It gives me 0 all the time in new column 'new_dummy'.

Sachin Kohli Over a year ago

If you are getting all 0 for all records then only reason I can think of can be possible if your one or all of dummy (1/2/3) variables are integers not strings... & if that's the case then either convert your dummy vars into string or edit apply-lambda code like str(x['dummy1'])...

OgeiD Over a year ago

It was the string... Thank you!

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