How to Avoid IndexError When Building Lists in Python?

List Assignment Error and Append Function

While attempting to create a list by assigning elements iteratively, you might encounter an IndexError, specifically at the line where you assign a value to an index. This error occurs because, unlike arrays in other languages, Python lists do not allow assigning values to non-existent indices.

To resolve this issue and successfully build a list from individual elements, replace the assignment syntax with the append function. Here's the corrected code:

i = [1, 2, 3, 5, 8, 13]
j = []
k = 0

for l in i:
    j.append(l)
    k += 1

Alternatively, create a list of the same length as the original list, but initialize its elements with None. Subsequently, overwrite the values in specific positions:

i = [1, 2, 3, 5, 8, 13]
j = [None] * len(i)
k = 0

for l in i:
   j[k] = l
   k += 1

Using the append function or pre-creating the list ensures that you can append elements without causing an IndexError.

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