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This seems like something Python would have a shortcut for. I want to append an item to a list N times, effectively doing this:
l = [] x = 0 for i in range(100): l.append(x) It would seem to me that there should be an "optimized" method for that, something like:
l.append_multiple(x, 100) Is there?
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You can use the sequence method list. extend to extend the list by multiple values from any kind of iterable, being it another list or any other thing that provides a sequence of values. So you can use list. append() to append a single value, and list.
append() will place new items in the available space. Lists are sequences that can hold different data types and Python objects, so you can use . append() to add any object to a given list. In this example, you first add an integer number, then a string, and finally a floating-point number.
For immutable data types:
l = [0] * 100 # [0, 0, 0, 0, 0, ...] l = ['foo'] * 100 # ['foo', 'foo', 'foo', 'foo', ...] For values that are stored by reference and you may wish to modify later (like sub-lists, or dicts):
l = [{} for x in range(100)] (The reason why the first method is only a good idea for constant values, like ints or strings, is because only a shallow copy is does when using the <list>*<number> syntax, and thus if you did something like [{}]*100, you'd end up with 100 references to the same dictionary - so changing one of them would change them all. Since ints and strings are immutable, this isn't a problem for them.)
If you want to add to an existing list, you can use the extend() method of that list (in conjunction with the generation of a list of things to add via the above techniques):
a = [1,2,3] b = [4,5,6] a.extend(b) # a is now [1,2,3,4,5,6] If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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