for loops with lots of if conditions while creating a new column-CodePudding

I am trying to convert 1 column (kinda 2) of categories (strings) into a set of numbers 1 for star, 2 qso, 3 for galaxies that are not agn (second column defines that) and then 4 for galaxies that are AGN.all saved on a new column of the dataframe.

for n ,i, l in zip(data_clean['class'], data_clean['subClass'], data_clean['nClass'] ): 
if n == 'STAR':
    l = 1
elif n == 'QSO':
    l=2
elif n == 'GALAXY' and i != 'AGN':
    l=3
elif  n == 'GALAXY' and i == 'AGN': 
   l=4

where class is the major category, subclass where I get the AGN classification and the nclass is the new column where I put the new integer classification. But I get all zeros. What am I doing wrong?

CodePudding user response：

Does this do what you want?

def type_to_value(n, i):
    if n == 'STAR':
        return 1
    elif n == 'QSO':
        return 2
    elif n == 'GALAXY' and i != 'AGN':
        return 3
    elif n == 'GALAXY' and i == 'AGN': 
        return 4

data_clean['nClass'] = [type_to_value(n, i) for n, i in zip(data_clean['class'], data_clean['subClass'])]

CodePudding user response：

There is no indentations on your for loop?

Try:

for n ,i, l in zip(data_clean['class'], data_clean['subClass'], data_clean['nClass'] ): 
    if n == 'STAR':
       l = 1
    elif n == 'QSO':
       l=2
    elif n == 'GALAXY' and i != 'AGN':
       l=3
    elif  n == 'GALAXY' and i == 'AGN': 
       l=4

I can't use tab here, so just try to do equal in your code. Don't copy and paste.