在 dataframe 中，如何根据另一列的条件在另一列中写入字符串

Question

I have an accounting trial balance (tb) in excel that I loaded as a df in python. The df has an index column on the left, starting with 0. column 1 is the account name, column 2 are the debits, and column 3 are the credits. Each row is an account with either a debit or credit balance. The tb has a "totals" row at the end, with the totals for debits and credits in columns 2 and 3. The debit and credit totals equal each other.

I would like to create a new "account #" column and give each account a number. These numbers should be from 1 to however many accounts there are, up to and not including the totals row. The account # in the totals row should be blank.

I wrote the following for loop, but it continues to assign an account number in the totals row:

for i in df['Account']:
    if i == 'TOTAL':
        df['account #'] == ''
    else:
        df['account #'] = df.index + 1

What can I do to have the account # for "totals" be blank?

Answer 1

We can do

import numpy as np 

df['account #']=np.where(df['Account']=='TOTAL', '' , df.index+1)