Python. How to remove zeroes from a list in Python

Question

X = [0,5,0,0,3,1,15,0,12]

for value in range(0,len(X)):

    if X[value] <= 0:
        del X[value]
        print(X)
print(X)

I run the code but then i get an error saying that the list is out of index range. Can someone please help me out on how to correct this mistake

You have your data structures mixed up- `del X[value]` is what you would use if you were accessing a dictionary, `X` is a list — Benjamin James, Apr 23 '18 at 05:19
Thanks. I recently started programming so i dont know the differences. But thanks for the help. I really appreciate it. I have to learn these stuff for my exam on Tuesday — Andrews, Apr 23 '18 at 05:30

score 29 · Answer 1 · answered Apr 23 '18 at 05:09

29

Try a list comprehension.

X = [0,5,0,0,3,1,15,0,12]
X = [i for i in X if i != 0]

answered Apr 23 '18 at 05:09

JahKnows

Thanks very much. So will it print it straight away with no zeroes. I will try code soon. – Andrews Apr 23 '18 at 05:31

score 7 · Answer 2 · answered Apr 23 '18 at 05:09

7

>>> X = [0,5,0,0,3,1,15,0,12]
>>> list(filter(lambda num: num != 0, X))
[5, 3, 1, 15, 12]

answered Apr 23 '18 at 05:09

pramesh

Thanks. And I have a question. I have seen the function lambda on multiple questions. What does it actually do. Thanks – Andrews Apr 23 '18 at 05:33
lambda functions are one line anonymous functions – pramesh Apr 23 '18 at 05:45

2 Answers2