How to create a new column in python & pandas

Question

I am trying to create a new column, not with the existing values of the current column, but with new values. I went ahead and created a function to do this, however, I am getting an error. The result I want is each municipality to have a code number i.e TO =1, SC=2 etc.

def ET(ET):
    return "ET" == 1
def TO(TO):
    return "TO" == 2
def NY(NY):
    return "NY" == 3
def SC(SC):
    return "SC" == 4
def coded_municipality(row):
    if row['coded_municipality'] == "ET" :
        return 1
    if row['coded_municipality'] == "NY" :
        return 2
    if row['coded_municipality'] == "SC" :
        return 3
    if row['coded_municipality'] == "TO" :
        return 4

marriage_data['Code'] = marriage_data.apply(lambda row : coded_municipality(row),axis=1)

However, I am still getting an error saying 'coded_municipality', 'occurred at index 0'

What am I doing wrong?

Vaishali · Accepted Answer · 2017-04-11 19:27:30Z

2

You can use map.

d = {"ET": 1, "TO": 2, "NY": 3, "SC": 4}
marriage_data['Code'] = marriage_data['coded_municipality'].map(d)

answered Apr 11, 2017 at 19:27

Vaishali

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