How to delete elements with condition below for loops?

Question

Hello i have a code like this :

def remove_something (token):
    temp_token = token
    for t in token :
        if len(t) == 5:
            temp_token.remove(t)
    return temp_token
    
a = ['abcde','abcde','abcde','ef','ghi']
print(remove_something(a))

That output should be like this :

['ef', 'ghi']

But why like this ? :

['abcde', 'ef', 'ghi']

`temp_token = token` doesn't make a copy of the list. You're removing from the same list you're iterating over. — Barmar, Jun 10 '21 at 15:21
Why not use a list comprehension? `return [t for t in token if len(t) != 5]` — Barmar, Jun 10 '21 at 15:23
Also this is a good explanation why: https://stackoverflow.com/a/6260097/8067109 — bca, Jun 10 '21 at 15:30

score 0 · Answer 1 · answered Jun 10 '21 at 15:23

Use .copy() in order to make a copy of a certain variable. This way you can modify this copy without modifying the original variable.

def remove_something (token):
    temp_token = token.copy()
    for t in token :
        if len(t) == 5:
            temp_token.remove(t)
    return temp_token
    
a = ['abcde','abcde','abcde','ef','ghi']
print(remove_something(a))

output

['ef', 'ghi']

score 0 · Answer 2 · answered Jun 10 '21 at 15:24

0

Use list comprehension instead:

a = ['abcde','abcde','abcde','ef','ghi']
b = [x for x in a if len(x) != 5]
print(b)
# ['ef', 'ghi']

answered Jun 10 '21 at 15:24

Timur Shtatland

12,024
2
30
47

score 0 · Answer 3 · answered Jun 10 '21 at 15:29

0

Using List comprehension

  x = [token for token in a if len(token) != 5 ]
  print(x)

output
['ef', 'ghi']

answered Jun 10 '21 at 15:29

Rima

1,447
1
6
12

How to delete elements with condition below for loops?

3 Answers3