CODEWITHSUNDEEP
pythonnumpymatrix
Oldy
Oldy

Reputation: 5

Check if two 1-D arrays are equal

This is the code I've tried:

import numpy as np

a = np.array([
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
])

if a[0] == [1, 2, 3]:
    print("equal")

And this is the error I'm getting:

Exception has occurred: ValueError
The truth value of an array with more than one element is ambiguous. 
Use a.any() or a.all()

Upvotes: 0

Views: 210

Answers (2)

Tonechas
Tonechas

Reputation: 13743

You could simply use numpy.array_equal:

In [32]: if np.array_equal(a[0], [1, 2, 3]):
    ...:     print("equal")
equal

Upvotes: 1

user17242583
user17242583

Reputation:

Just use np.all(), as the error message tells you. Doing == on a numpy array will return an that's the same shape as the original array, only with True and False values in. They'll be True if the items at the particular index are equal, and False otherwise. .all() will only return True if every item in the array is True, so it will return True if the arrays are perfectly equal:

if np.all(a[0] == [1, 2, 3]):
    print("equal")

Output:

equal

Upvotes: 0

Related Questions