Python Error IndexError: list assignment index out of range

Question

Here is my function's code:

    import random

    def generate(n):

        res = [0]
        x = [0]
        while x == 0:
            x[0] = random.randint(0, 9)
            res = res[0].append(x[0])
        for i in range(1, n - 1):
            x[i] = random.randint(0, 9)
            res[i] = res[i].append(x[i])
        return res

Main program code:

    import number
    n = 20
    f = number.generate(n)
    s = []
    s = number.counter()
    print("{0}" .format(s))

When I run the program I get:

   Traceback (most recent call last):
   f = number.generate(n)
   x[i] = random.randint(0, 9)
   IndexError: list assignment index out of range

Could you tell me how to fix this? Thanks : )

Read a python tutorial because your code has problems in every other line. — halex
– halex, Commented Mar 23, 2015 at 6:39
Perhaps read this? ericlippert.com/2014/03/05/how-to-debug-small-programs — Paul Hankin
– Paul Hankin, Commented Mar 23, 2015 at 6:48

Ashique PS · Accepted Answer · 2015-03-23 06:44:00Z

3

The reason for this error is you are accessing x[0 to n] where you assigned only x[0]. The list have only one index and you are accessing higher indexes. Thats why you are getting list index out of range.

Use this function to generate list of random numbers.

def generate(n):
    return [random.randint(0,9) for i in range(n)]

answered Mar 23, 2015 at 6:44

Ashique PS

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Comments

chw21 · Accepted Answer · 2015-03-23 06:47:31Z

2

You initialise two lists with size 1. When you then try to access the element with index 1 you get an index error.

Try this first:

import random
def generate(n):
    x = [random.randint(1, 9)] + [random.randint(0, 9) for _ in range(n-1)]
    return x

edited Mar 23, 2015 at 6:47

answered Mar 23, 2015 at 6:39

chw21

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Tarun Gaba · Accepted Answer · 2015-03-23 06:39:03Z

1

you use append method to add to a list.

x.append (val-to-add-to-list)

for i in range(1, n - 1): 
    x.append (random.randint(0, 9)) 
    res.append(x[i]) 

return res

answered Mar 23, 2015 at 6:39

Tarun Gaba

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Marcin · Accepted Answer · 2015-03-23 06:39:03Z

1

Your x is a list that has only one element, i.e. 0.

In this line: x[i] = random.randint(0, 9) your first i is equal to 1, thus you are out of range.

answered Mar 23, 2015 at 6:39

Marcin

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