Removing elements from a list based on indices in another list in Python

Question

I have a list J. I want to remove specific elements from J[0] based on index. For example, I want to remove J[0],J[3] based on elements in index. But I am getting an error. I present the expected output.

J=[[2, 6, 9, 10]]

index=[[0,3]]

for i in range(0,len(J)):
    for k in range(0,len(index)): 
        J[i].remove(index[k][0])
print(J)

The error is

 in <module>
    J[i].remove(index[k][0])

ValueError: list.remove(x): x not in list

The expected output is

[6,9]

Asked By: isaacmodi123

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Source

Answer 1

Try list comprehension / filtering (and fix the [0] as required):

new_J = [j for i,j in enumerate(J[0]) if i not in index[0]]

Answered By: Julien

Answer 2

Well in this code you loop your code only 1 time for j and index because both len(j) and len(index) is 1.

Try this:

J=[2, 6, 9, 10]

index=[0,3]

for i in range(len(index)):
    J.pop(index[i] - i)

print(J)

Answered By: OnurEmre Yıldırım

Removing elements from a list based on indices in another list in Python

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