How to assign calculations done in a for loop by row to blank columns by index?

Question

I have a dataframe that looks like this (with more rows):

   Buy      Sell      acct_stock      usd_account
0  True     False
1  False    True

I assigned two numerical values to two variables like so:

account = 1000
stock_amount = 0

For each row in the df that has the combination of True AND False, I want to update columns acct_stock and usd_account by using the numerical variables to do calculations:

I have come up with the following FOR loop:

for index,row in df.iterrows():


    if (row['Buy'] == True & row['Sell'] == False):
        row['acct_stock'] = (account * 0.02)/row[4]
        row['usd_account'] = account - (stock_amount * 0.02)

When I run this the columns acct_stock and usd_account do not get updated at all, even for rows where the conditions are met.

What am I doing wrong that the calculations are not being assigned by index to the columns/rows in question and the variables 'account' and 'stock_amount' are also being updated continously?

score 1 · Accepted Answer · answered Apr 11 '20 at 03:46

1

The answer of why is didn't work is included in this page, The code you need to look at is here

However keep in mind you need to have those column first before you can set a value

answered Apr 11 '20 at 03:46

Michael Hsi

439
2
8

I figured it out, it was what you mentioned plus I was not using `and` but instead `&`. Thank you – RustyShackleford Apr 11 '20 at 03:47
oh yeah, you can only use and in python, but within df.loc[ ] you'd use & – Michael Hsi Apr 11 '20 at 03:48

How to assign calculations done in a for loop by row to blank columns by index?

1 Answers1