How to query pandas dataframe using a specific value?

Question

I have pandas dataframe with the following contents:

    A   B     C  D
0 red, t1, blue, 1
1 red, t1, yellow, 2
2 red, t0, green, 1
3 red, t0, blue, 1
4 red, t0, blue, 2
5 green, t1, yeallow, 1
6 green, t0, red, 1
7 green, t0, yellow, 1
8 blue, t0, yellow, 1
9 blue, t1, red, 1
10 yellow, t1, red, 3

How to extract all the rows that for A equal to 'green' AND for B equal to t0 for example?

`df[df.A.str.contains("green") & df.B.str.contains("t0")]` since you used the word "contain". If you want exact matching, `df[(df.A == "green") & (df.B == "t0")]` — ayhan, Mar 28 '16 at 16:30
Did you check this? http://stackoverflow.com/questions/26640129 — Gurupad Hegde, Mar 28 '16 at 16:34
I do not like how the question is formulated in the link you provided. So, I think it is better to have a separate question with an example and a short answer, as given by @ayhan — minerals, Mar 28 '16 at 16:35
This will not detect the colors in column C, but you can adjust the approach as follows. Define `set_of_needed_words`. Write `df = df[df.apply(lambda s: s.isin(set_of_desired_words))]`. — hilberts_drinking_problem, Mar 28 '16 at 16:36
@minerals It is not a problem to be a dupe. Now this post will serve as a signal to the other, Not something to worry about. Cheers :) — Bhargav Rao, Mar 28 '16 at 18:53

score 2 · Accepted Answer · answered Mar 28 '16 at 16:39

2

As answered by @ayhan,

Partial string match:

df[df.A.str.contains("green") & df.B.str.contains("t0")]

Exact string match:

df[(df.A == "green") & (df.B == "t0")]

answered Mar 28 '16 at 16:39

minerals

6,090
17
62
107

This works, but obviously only for columns `A` and `B`. So the row like `['red', 't1', 'green', 0]` will be omitted. I am not clear if this is in line with your intent. – hilberts_drinking_problem Mar 28 '16 at 16:44
Sorry, in my question I meant exactly that (corrected the question). – minerals Mar 28 '16 at 17:15

How to query pandas dataframe using a specific value?

1 Answers1