CODEWITHSUNDEEP
pythonnumpy
Daniel
Daniel

Reputation: 239

Filter a numpy array by function

I have a 2D numpy array in the following form:

array([[0, 4],
       [1, 5],
       [2, 6]])

I want to filter out the rows that their first value is bigger than 1, but I couldn't find a numpy function to do so.

I know that I can use filter:

np.array(list(filter((lambda x: x[0] <= 1), my_arr)))

This approach is not efficient, since I need to convert the result into list and only than into numpy array. Is there a better way?

Upvotes: 2

Views: 834

Answers (2)

Mozhdeh Ahmadi
Mozhdeh Ahmadi

Reputation: 1

import numpy as np

arr=np.array([[0, 4],
       [1, 5],
       [2, 6]])

newarr=[]

for fetch in arr:
    if(fetch[0]>1):
        newarr.append(fetch)
        
print(newarr)

Upvotes: 0

juanpa.arrivillaga
juanpa.arrivillaga

Reputation: 95873

There is not numpy interface to do this efficiently with a function. However, in this particular case, you just want something like:

>>> import numpy as np
>>> arr = np.array([[0, 4],
...        [1, 5],
...        [2, 6]])
>>> arr[arr[:,0] <= 1]
array([[0, 4],
       [1, 5]])

Upvotes: 2

Related Questions