CODEWITHSUNDEEP
pythonlist
Peter Jeppo
Peter Jeppo

Reputation: 57

Creating lists of increasing length python

Hey i was wondering if anyone knew how to create a list of 10 lists of increasing length. The first list should be empty, i.e., len(mylist[0]) == 0; the second list should have one element, so len(mylist[1]) == 1; and so on. I have been trying to use extend,append and insert but to no avail

So far i have been able to create 10 lists with no elements

def mylists(x):    
    d = [[] for x in range(0,x)]
    return d

print (mylists(10)

Any help would be greatly appreciated!

Upvotes: 2

Views: 2125

Answers (3)

robmathers
robmathers

Reputation: 3638

Try this:

super_list = []
for i in range(10):
    super_list.append(list(range(i))) # .append(range(i)) suffices for python2

You may want to tweak the ranges, depending on your desired outcome. 10 iterations of that will give you ten lists, like so:

[[],
 [0],
 [0, 1],
 [0, 1, 2],
 [0, 1, 2, 3],
 [0, 1, 2, 3, 4],
 [0, 1, 2, 3, 4, 5],
 [0, 1, 2, 3, 4, 5, 6],
 [0, 1, 2, 3, 4, 5, 6, 7],
 [0, 1, 2, 3, 4, 5, 6, 7, 8]]

If you feel like doing it in a more functional way, this will achieve the same result in Python 2:

map(range, range(10))

Or in Python 3:

list(map(lambda i: list(range(i)), range(10)))

Upvotes: 1

Kallz
Kallz

Reputation: 3523

>>> [[i for i in range(n)] for n in range(1,8,1)]
[[0], [0, 1], [0, 1, 2], [0, 1, 2, 3], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4, 5], [0, 1, 2, 3, 4, 5, 6]]

For using method

>>> def test(n):
...     return [[i for i in range(m)] for m in range(1,n+2,1)]
... 
>>> 
>>> print test(5)
[[0], [0, 1], [0, 1, 2], [0, 1, 2, 3], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4, 5]]

Upvotes: 0

user1785721
user1785721

Reputation:

You can do:

print([[i]*i for i in range(10)])

Upvotes: 1

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