Pandas: Check if row exists with certain values

问题

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.

回答1:

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.

回答2:

an easier way is:

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

回答3:

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

index_list = df[(df['A'] == 2)&(df['B'] == 3)].index.tolist()

来源：https://stackoverflow.com/questions/24761133/pandas-check-if-row-exists-with-certain-values