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python - Extending list returns None


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The function extend is an in-place function i.e. It will make the changes to the original list itself. From the docs

Extend the list by appending all the items in the given list; equivalent to a[len(a):] = L.

Hence you do not need to re-assign it back to the list variable.

You can do

list1 = ['hi','how','are','you','googl']
ok = 'item22'
list1.extend([ok])   # Notice brackets here

Then when you print list it will print

['hi','how','are','you','googl','item22']

Better way

Using append as mentioned below is the better way to do it.

list1 = ['hi','how','are','you','googl']
ok = 'item22'
list1.append(ok)   # Notice No brackets here

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