Shows "String index out of range" when using a loop

Question

I'm trying to write a code that makes the first letter of every line in uppercase, but it is unable to execute past the 6th line if l[0].islower(): . The l[0] works fine when it's outside the loop, but is always says "String Index out of range" when I put it back in the loop.

m = open(r"C:\Users\■■■■■■\Desktop\■■■■\other.txt","r", encoding = "utf-8") #Just blocking the text out

while True:
    l = m.readline()

    if l[0].islower():
        l.replace(l[0],l[0].upper())
        
    print(l)
    
    if not l:
        break
m.close()

Why are you looping that way? Why not just for line in m? Anyway you should put the if not l right after reading l, not in the end — Tomerikoo
– Tomerikoo, Commented Aug 27, 2020 at 9:45
Also, doing replace(l[0], ...) will replace all occurrences of that letter, not just the first — Tomerikoo
– Tomerikoo, Commented Aug 27, 2020 at 9:49

Josef · Accepted Answer · 2020-08-27 09:44:26Z

1

See capitalize(), its probably what you want.

Also you can iterate a file line by line much easier.

path = r"other.txt"
with open(path, 'r') as file:
    for line in file:
        print(line.capitalize())

answered Aug 27, 2020 at 9:44

Josef

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Comments

ghost · Accepted Answer · 2020-08-27 09:34:51Z

0

Put the check at the beginning of the loop rather than the end because you go on to access l[0] even if l is None.

while True:

    l = m.readline()
    if not l:
        break

    if l[0].islower():
        l.replace(l[0],l[0].upper())
        
    print(l)
    
m.close()

answered Aug 27, 2020 at 9:34

ghost

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Comments

AM Z · Accepted Answer · 2020-08-27 09:46:46Z

0

with open("content.txt", 'r') as file:

    while 1:
        content = file.readline()
        if not content:
            break

        print(content.capitalize())

print("Done !")

you can use this.

answered Aug 27, 2020 at 9:46

AM Z

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