[FIXED] Python Pandas Dataframe - consider only first occurrence in column [Combined Decision]

Issue

So, for these 2 columns, [Decision_A], [Combined_Decision], is there a way that I only take first occurrence of [Combined_Decision] == TRUE while subsequent "TRUE" can be ignored until next "TRUE" appears in [Decision_A] in pandas dataframe?

Dataframe columns be like

Solution

Just iterate over all of the rows while checking for the appropriate conditions. Use some sort of flag to maintain whether there has been a True in the first column since the last desired result.

The following self-contained example should achieve roughly what you want, putting a 1 in the desired_result column if conditions are met. The way I implemented it, if there are True values in both cells of the same row, this yields a desired result.

import pandas as pd


df = pd.DataFrame({'Decision_A': [False, False, False, True, False, False, True, False, False],
                   'Combined_Decision': [True, False, False, False, True, False, True, True, True]})

A_flag = False
df['desired_result'] = 0

for i, row in df.iterrows():
    if row['Decision_A'] == True:
        A_flag = True
    if A_flag == True and row['Combined_Decision'] == True:
        A_flag = False
        df.loc[i, 'desired_result'] = 1

print(df)

gives

   Decision_A  Combined_Decision  desired_result
0       False               True               0
1       False              False               0
2       False              False               0
3        True              False               0
4       False               True               1
5       False              False               0
6        True               True               1
7       False               True               0
8       False               True               0

P.S. Making good reproducible examples for pandas questions will likely get you answers more quickly here.

Answered By - Frodnar