CODEWITHSUNDEEP
pythonpython-3.xpandas
Fernando S. Peregrino
Fernando S. Peregrino

Reputation: 515

How to get rows where a set of columns are equal to a given value in Pandas?

I have a dataframe with many columns (around 1000). Given a set of columns (around 10), which have 0 or 1 as values, I would like to select all the rows where I have 1s in the aforementioned set of columns.

Toy example. My dataframe is something like this:

c1,c2,c3,c4,c5
'a',1,1,0,1
'b',0,1,0,0
'c',0,0,1,1
'd',0,1,0,0
'e',1,0,0,1

And I would like to get the rows where the columns c2 and c5 are equal to 1:

'a',1,1,0,1
'e',1,0,0,1

Which would be the most efficient way to do it?

Thanks!

Upvotes: 0

Views: 55

Answers (3)

sophros
sophros

Reputation: 16660

import pandas as pd

frame = pd.DataFrame([
['a',1,1,0,1],
['b',0,1,0,0],
['c',0,0,1,1],
['d',0,1,0,0],
['e',1,0,0,1]], columns='c1,c2,c3,c4,c5'.split(','))

print(frame.loc[(frame['c2'] == 1) & (frame['c5'] == 1)])

Upvotes: 0

Zero
Zero

Reputation: 76917

This would be more generic for multiple columns cols

In [1277]: cols = ['c2', 'c5']

In [1278]: df[(df[cols] == 1).all(1)]
Out[1278]:
    c1  c2  c3  c4  c5
0  'a'   1   1   0   1
4  'e'   1   0   0   1

Or,

In [1284]: df[np.logical_and.reduce([df[x]==1 for x in cols])]
Out[1284]:
    c1  c2  c3  c4  c5
0  'a'   1   1   0   1
4  'e'   1   0   0   1

Or,

In [1279]: df.query(' and '.join(['%s==1'%x for x in cols]))
Out[1279]:
    c1  c2  c3  c4  c5
0  'a'   1   1   0   1
4  'e'   1   0   0   1

Upvotes: 1

Jonathan DEKHTIAR
Jonathan DEKHTIAR

Reputation: 3536

Can you try doing something like this:

df.loc[df['c2'] == 1 & df['c5'] == 1]

Upvotes: 0

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