Python 3 turn range to a list
You can just construct a list from the range object:
my_list = list(range(1, 1001))
This is how you do it with generators in python2.x as well. Typically speaking, you probably don't need a list though since you can come by the value of my_list[i]
more efficiently (i + 1
), and if you just need to iterate over it, you can just fall back on range
.
Also note that on python2.x, xrange
is still indexable1. This means that range
on python3.x also has the same property2
1print xrange(30)[12]
works for python2.x
2The analogous statement to 1 in python3.x is print(range(30)[12])
and that works also.
In Pythons <= 3.4 you can, as others suggested, use list(range(10))
in order to make a list out of a range (In general, any iterable).
Another alternative, introduced in Python 3.5
with its unpacking generalizations, is by using *
in a list literal []
:
>>> r = range(10)
>>> l = [*r]
>>> print(l)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
Though this is equivalent to list(r)
, it's literal syntax and the fact that no function call is involved does let it execute faster. It's also less characters, if you need to code golf :-)
in Python 3.x, the range()
function got its own type. so in this case you must use iterator
list(range(1000))
The reason why Python3 lacks a function for directly getting a ranged list is because the original Python3 designer was quite novice in Python2. He only considered the use of range()
function in a for loop, thus, the list should never need to be expanded. In fact, very often we do need to use the range()
function to produce a list and pass into a function.
Therefore, in this case, Python3 is less convenient as compared to Python2 because:
- In Python2, we have
xrange()
andrange()
; - In Python3, we have
range()
andlist(range())
Nonetheless, you can still use list expansion in this way:
[*range(N)]
You really shouldn't need to use the numbers 1-1000 in a list. But if for some reason you really do need these numbers, then you could do:
[i for i in range(1, 1001)]
List Comprehension in a nutshell:
The above list comprehension translates to:
nums = []
for i in range(1, 1001):
nums.append(i)
This is just the list comprehension syntax, though from 2.x. I know that this will work in python 3, but am not sure if there is an upgraded syntax as well
Range starts inclusive of the first parameter; but ends Up To, Not Including the second Parameter (when supplied 2 parameters; if the first parameter is left off, it'll start at '0')
range(start, end+1)
[start, start+1, .., end]