Python Forum

Hi, I have a question about the string method 'find(...)'.

Consider the string 'tomato potato gelato'. How would I frame an optional argument such that the indexing would only begin at 'gelato'? In general terms, what I am trying to learn here is how to read function descriptions, because I don't get how the optional arguments work on the basis of the following description.

find(...)
 |      S.find(sub[, start[, end]]) -> int
 |      
 |      Return the lowest index in S where substring sub is found,
 |      such that sub is contained within S[start:end].  Optional
 |      arguments start and end are interpreted as in slice notation.

Thanks

Output:mississippi
   ^  ^
   3  6

>>> 'mississippi'.find('si')
3
>>> 'mississippi'.find('si', 5)
6

Do you know why the following method call is returning this?

>>> 'si si si no yes si'.find('i', 6, 10)
7

I want it to return in failure, i.e. -1

for index, ch in enumerate('si si si no yes si'):
    print(f'{index} --> {ch}')
print('si si si no yes si'.find('i', 8, 10))

Output:0 --> s
1 --> i
2 -->
3 --> s
4 --> i
5 -->
6 --> s
7 --> i
8 -->
9 --> n
10 --> o
11 -->
12 --> y
13 --> e
14 --> s
15 -->
16 --> s
17 --> i
-1
>>>

as you can see, 'i' is on index 1, 4, 7 and 17. with start=6 and end=10 you catch the 'i' on index 7

ClassicalSoul

buran

ClassicalSoul

buran