Pandas: Check if row exists with certain values

2019-02-04 11:58发布

I have a two dimensional (or more) pandas DataFrame like this:

>>> import pandas as pd
>>> df = pd.DataFrame([[0,1],[2,3],[4,5]], columns=['A', 'B'])
>>> df
   A  B
0  0  1
1  2  3
2  4  5

Now suppose I have a numpy array like np.array([2,3]) and want to check if there is any row in df that matches with the contents of my array. Here the answer should obviously true but eg. np.array([1,2]) should return false as there is no row with both 1 in column A and 2 in column B.

Sure this is easy but don't see it right now.

3条回答
别忘想泡老子
2楼-- · 2019-02-04 12:05

If you also want to return the index where the matches occurred:

index_list = df[(df['A'] == 2)&(df['B'] == 3)].index.tolist()
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smile是对你的礼貌
3楼-- · 2019-02-04 12:07

Turns out it is really easy, the following does the job here:

>>> ((df['A'] == 2) & (df['B'] == 3)).any()
True
>>> ((df['A'] == 1) & (df['B'] == 2)).any()
False

Maybe somebody comes up with a better solution which allows directly passing in the array and the list of columns to match.

Note that the parenthesis around df['A'] == 2 are not optional since the & operator binds just as strong as the == operator.

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狗以群分
4楼-- · 2019-02-04 12:21

an easier way is:

a = np.array([2,3])
(df == a).all(1).any()
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