How to delete row when iterating into pandas Dataframe column?

Question

This is my csv file:

A  B  C  D  J
0  1  0  0  0
0  0  0  0  0
1  1  1  0  0
0  0  0  0  0
0  0  7  0  7

I need each time to select two columns and I verify this condition if I have Two 0 I delete the row so for exemple I select A and B

And Then I select A and C ..

I used This code for A and B but it return errors

import pandas as pd 
df = pd.read_csv('Book1.csv')

a=df['A']
b=df['B']

indexes_to_drop = []

for i in df.index:
   if df[(a==0) & (b==0)] :
   indexes_to_drop.append(i)

df.drop(df.index[indexes_to_drop], inplace=True )

Any help please!

so you need to check every combinations of columns? can you explain the problem — anky
– anky, Commented Jul 4, 2019 at 16:04

Erfan · Accepted Answer · 2019-07-04 16:06:34Z

1

First we make your desired combinations of column A with all the rest, then we use iloc to select the correct rows per column combination:

idx_ranges = [[0,i] for i in range(1, len(df.columns))]
dfs = [df[df.iloc[:, idx].ne(0).any(axis=1)].iloc[:, idx] for idx in idx_ranges]

print(dfs[0], '\n')
print(dfs[1], '\n')
print(dfs[2], '\n')
print(dfs[3])

   A  B
0  0  1
2  1  1 

   A  C
2  1  1
4  0  7 

   A  D
2  1  0 

   A  J
2  1  0
4  0  7

answered Jul 4, 2019 at 16:06

Erfan

43.3k10 gold badges75 silver badges86 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

ALollz · Accepted Answer · 2019-07-05 22:25:15Z

1

Do not iterate. Create a Boolean Series to slice your DataFrame:

cols = ['A', 'B']

m = df[cols].ne(0).any(1)
df.loc[m]

   A  B  C  D  J
0  0  1  0  0  0
2  1  1  1  0  0

You can get all combinations and store them in a dict with itertools.combinations. Use .loc to select both the rows and columns you care about.

from itertools import combinations

d = {c: df.loc[df[list(c)].ne(0).any(1), list(c)]
     for c in list(combinations(df.columns, 2))}

d[('A', 'B')]
#   A  B
#0  0  1
#2  1  1

d[('C', 'J')]
#   C  J
#2  1  0
#4  7  7

edited Jul 5, 2019 at 22:25

answered Jul 4, 2019 at 15:55

ALollz

59.7k7 gold badges73 silver badges97 bronze badges

1 Comment

ALollz Over a year ago

@OumaymaHamdi I see, I've added a solution for all two-pair combinations.

Collectives™ on Stack Overflow

How to delete row when iterating into pandas Dataframe column?

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related