Populating a list in python using for loop

Question

a = int(input())
l1 = []
for i in range(a):
    l1[i] = 5

print(l1)

I keep getting the error:

list assignment index out of range

i will always be smaller than a so why am I getting this error? I don't wish to use append() .

Answer 1

You could use this if you want to get a list of n '5' elements:

a = int(input())
l1 = [5 for _ in range(a)]
print l1

It will wait for input and save the list in the l1 list

Answer 2

Use insert .

a = int(input())
l1 = []
for i in range(a):
    l1.insert(999999999999,5)

print(l1)

Executing:

 10
[5, 5, 5, 5, 5, 5, 5, 5, 5, 5]

Answer 3

You are referring to the i -th element, but your list is empty. It has to have a i -th element to write a[i] = 5 . So, populate your list with a dummy value. eg, start with l1 = [None] * a instead of l1 = [] .

Answer 4

You might be confusing the behavior of list to dictionary. Dictionary would work.

a = int(input())
l1 = {}
for i in range(a):
    l1[i] = 5  

print([j for i,j in l1.items()])

You got an error because there exists no element at l1[0] to be assigned users input. If we were to make your code work, we need to pre-populate the list with dummies.

a = int(input())
l1 = (','*(a-1)).split(',')
for i in range(a):
    l1[i] = 5

print(l1)