Check if array is part of a bigger array

Question

I am trying to check if a 1 dimensional numpy array is a part of a bigger, 2 dimensional array. I could do this with many for-loops but I guess there is a more pythonic way to do so.

The attempt I have to far:

1darray = np.array([0,0,0])
2darray = np.array([[0,0,1],[0,1,0],[1,0,0]]) 
1darray in 2darray

But this code returns a True , as long as one of the elements from 1darray occures somewhere in 2darray. But I want to check if the whole array is a row in the bigger one, so I would want this code to return False, while I would want this code to return True:

1darray = np.array([0,0,1])
2darray = np.array([[0,0,1],[0,1,0],[1,0,0]]) 
1darray in 2darray

I would appreciate any help, Thanks already!

Possible duplicate of How to check if an array is in another array in Python — Austin
– Austin, Commented Mar 30, 2019 at 18:20

Jim Todd · Accepted Answer · 2019-03-30 18:17:04Z

5

You can use any() and all() function to achieve this.

>>> a=np.array([0,0,0])
>>> b=np.array([[0,0,1],[0,1,0],[1,0,0]])
>>> (a == b).all(axis=1).any()
False

>>> a=np.array([0,0,1])
>>> b=np.array([[0,0,1],[0,1,0],[1,0,0]])
>>> (a == b).all(axis=1).any()
True

answered Mar 30, 2019 at 18:17

Jim Todd

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1 Comment

FeWa Over a year ago

Thank you! That was exactly what I was looking for.

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