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+= and list.append() difference

What's the difference between my_list += [6] and my_list.append(6) ?

1 Answer

Hi Daffa

There is a difference, append just adds something to the original list where as += combines the two as its an assignment operator. list.append() is almost alot more efficient in terms of performance. Using the += operator is the same as saying list.extend().

hope this helps.

Seth Kroger
Seth Kroger
56,413 Points

Also to add to that, the difference between append() and extend() is that if you add a list append() will add the whole list as a single item (a list inside a list) while extend will add each element to the target list.

alist = [1, 2, 3, 4]

alist.append([5,6]) # gives you [1, 2, 3, 4, [5, 6]]
   # vs.
alist.extend([5,6]) or alist += [5, 6] # gives you [1, 2, 3, 4, 5, 6]

Thanks for the help!