如何在下面的代码中修复“IndexError：list index out of range”

Question

I have been running the following code o Jupyter Notebook 5.7.4 with Python 3.7.1. It worked fine there. When I tried to run the same code on HPC with python 3.5.2 I keep getting following error. if array[i-1] == array[i]: IndexError: list index out of range

import vcf
v = vcf.Reader(filename='/scratch/global/kkdesi01/Equine/animals/Chr/Chr11_possibleIntrogressionTargets.vcf')
f = open('/scratch/global/kkdesi01/Equine/animals/Chr/position11.txt', 'w+')
for record in v:
    f.write(str(record.POS))
    f.write('\n')
f.close()

with open('/scratch/global/kkdesi01/Equine/animals/Chr/position11.txt', 'r') as ins:
    array = []
    for line in ins:
        array.append(line)
print(len(array))

f = open('/scratch/global/kkdesi01/Equine/animals/Chr/filter11.txt', 'w+')
for i in range (1, len(array)):
    val1 = int(array [i-1])
    val2 = int(array [i])
    diff = val2-val1
    if diff < 10:
        f.write (str(val1))
        f.write ('\n')
        f.write (str(val2))
        f.write ('\n')
f.close()

with open('/scratch/global/kkdesi01/Equine/animals/Chr/filter11.txt', 'r') as ins:
    array = []
    for line in ins:
        array.append(line)
len(array)

for i in range(1, len(array)):
    if array[i-1] == array[i]:
        del array[i]

error if array[i-1] == array[i]: IndexError: list index out of range

I need help in understanding what needs to be changed in the code

Answer 1

See below what is the problem.

You modify the length of the array during the iteration.

User set in order to remove duplicates.

array = [2, 3, 4, 4, 4]
for i in range(1, len(array)):
    if array[i - 1] == array[i]:
        print('Remove entry at offset {}'.format(i))
        del array[i]

output

Remove entry at offset 3

    if array[i - 1] == array[i]:
IndexError: list index out of range