In this week's Python snippet post we're looking at the
extend method for lists.
extend is a lot like the
append method, but instead of adding a single value,
extend allows us to append several elements to the end of a given list object.
Let's start by defining a couple of lists:
l_1 = [1, 2, 3, 4] l_2 = [5, 6, 7, 8]
We're going to use
extend to add the values from
l_2 onto the end of
l_1.extend(l2) print(l_1) # [1, 2, 3, 4, 5, 6, 7, 8]
As we can see, the
extend method in an in-place operation, so it modifies the original list. Other than that, it perform very similarly to using the
+ operator with lists, so why should we care about
extend can accept any iterable, while using something like
+ to perform concatenation only works when both objects are lists. So we can do this:
[1, 2, 3] + [4, 5, 6]
While the following will give us a
[1, 2, 3] + (4, 5, 6)
extend on the other hand, everything works just fine:
l_1 = [1, 2, 3, 4] t_1 = (5, 6, 7, 8) l_1.extend(t_1) # [1, 2, 3, 4, 5, 6, 7, 8]
That's it for
extend! I hope you learnt something new, and I hope you can find places to use
extend in your own code.
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