Showing posts with label remove and pop on lists in python.. Show all posts
Showing posts with label remove and pop on lists in python.. Show all posts

Friday, 15 September 2017

Difference between del, remove and pop on lists in python.


remove removes the first matching value:
>>> a = [0, 2, 3, 2]
>>> a.remove(2)
>>> a
[0, 3, 2]
del removes a specific index:
>>> a = [3, 2, 2, 1]
>>> del a[1]
[3, 2, 1]
and pop returns the removed element:
>>> a = [4, 3, 5]
>>> a.pop(1)
3
>>> a
[4, 5]
Their error modes are different too:
>>> a = [4, 5, 6]
>>> a.remove(7)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: list.remove(x): x not in list
>>> del a[7]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: list assignment index out of range
>>> a.pop(7)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: pop index out of range

pop : Takes Index & returns Value
remove : Takes value, removes first occurrence and returns nothing
delete : Takes index, removes value at that index and returns nothing