Python find first occurrence of character after index

Question

I am trying to get the index of the first occurrence of a character that occurs in a string after a specified index. For example:

string = 'This + is + a + string'

# The 'i' in 'is' is at the 7th index, find the next occurrence of '+'
string.find_after_index(7, '+')

# Return 10, the index of the next '+' character
>>> 10

Answer 1

Python is so predicable:

>>> string = 'This + is + a + string'
>>> string.find('+',7)
10

Checkout help(str.find) :

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.

    Return -1 on failure.

Also works with str.index except that this will raise ValueError instead of -1 when the substring is not found.

Answer 2

You can use:

start_index = 7
next_index = string.index('+', start_index)

Answer 3

string.find('+', 7)

阅读文档 。

Answer 4

In [1]: str.index?
Docstring:
S.index(sub[, start[, end]]) -> int

Like S.find() but raise ValueError when the substring is not found.
Type:      method_descriptor

In [2]: string = 'This + is + a + string'

In [3]: string.index('+', 7)
Out[3]: 10

Answer 5

for i in range(index, len(string)):
    if string[i] == char:
         print(i)

The above code will loop through from the index you provide index to the length of the string len(string) . Then if the index of the string is equal to the character, char , that you are looking for then it will print the index.

You could put this in a function and pass in the, string, index and character and then return i.