I want to multiply two columns in a pandas DataFrame and add the result into a new column

Question

I\'m trying to multiply two existing columns in a pandas Dataframe (orders_df) - Prices (stock close price) and Amount (stock quantities) and add the calculation to a new co

Answer 1

To make things neat, I take Hayden's solution but make a small function out of it.

def create_value(row):
    if row['Action'] == 'Sell':
        return row['Prices'] * row['Amount']
    else:
        return -row['Prices']*row['Amount']

so that when we want to apply the function to our dataframe, we can do..

df['Value'] = df.apply(lambda row: create_value(row), axis=1)

...and any modifications only need to occur in the small function itself.

Concise, Readable, and Neat!