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Python Python Collections (2016, retired 2019) Lists Removing items from a list

derekverrilli
derekverrilli
8,841 Points
Posted by derekverrilli
derekverrilli
8,841 Points

I don't understand why this doesn't remove the nested list.

When I test the code in workspaces with

print(type(messy_list[-1]))

after the loop, it says it is <class 'list'>

I don't see why it doesn't get removed. It works for the string and Boolean values.

lists.py 
messy_list = ["a", 2, 3, 1, False, [1, 2, 3]]

# Your code goes below here
messy_list.insert(0, messy_list.pop(3))

for item in messy_list:
    if type(item) != int:
        messy_list.remove(item)

1 Answer

Christopher Shaw
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PLUS
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Christopher Shaw
Python Web Development Techdegree Graduate 58,248 Points
Christopher Shaw
.a{fill-rule:evenodd;}techdegree seal-36
Christopher Shaw
Python Web Development Techdegree Graduate 58,248 Points

It is a bad idea to remove items from the list you are iterating as this leads to unpredictable results. Rather just remove the items one at a time: messy_list.remove([1,2,3])

derekverrilli
derekverrilli
8,841 Points
derekverrilli
derekverrilli
8,841 Points

That seems very inefficient. What if it's a list containing 2000 items?