Why in python, when slicing a string, the substring is inclusive of the first index but not the second?

Asked Dec 05 '21 at 13:15

Active Dec 05 '21 at 13:26

Viewed 877 times

Just out of curiosity really. As an example, the following code in python

astring = 'abcdefg'
print(astring[0:3])

returns

abc

which is the first three indices of the string. But since the indices start at zero, we have that astring[0] is included in the substring but not astring[3]. Why? Wouldn't make more sense to have astring[0:3] be equal to 'abcd'?

asked Dec 05 '21 at 13:15

jonathan

index, length. where index starts at 0, and length starts at 1. meaning "take 3 characters form index 0" – Dean Van Greunen Dec 05 '21 at 13:22
1

@Dean .... `"that does not quite work that way"[2:5]` – Patrick Artner Dec 05 '21 at 13:23
2

it works like [x,y) in mathematics. – Moein Kameli Dec 05 '21 at 13:23
@PatrickArtner it does/ – Dean Van Greunen Dec 05 '21 at 13:24
https://www.geeksforgeeks.org/how-to-index-and-slice-strings-in-python/ – Dean Van Greunen Dec 05 '21 at 13:25
I think the question is really more https://stackoverflow.com/q/11364533/3001761, so I've added it to the dupe list – jonrsharpe Dec 05 '21 at 13:26
3

@dean `"that does not quite work that way"[2:5]"` does not give you pos 2 + 5 characters - it returs the characters at 2,3,4 - it is not the _lenght_ to be returned but the 2nd index wich is not included in the result. – Patrick Artner Dec 05 '21 at 13:30

Why in python, when slicing a string, the substring is inclusive of the first index but not the second?

0 Answers0