[英]Python: Find index of the first occurrence of x and then the index of the second occurrence of x
[英]Python find first occurrence of character after index
我試圖獲取指定索引后的字符串中出現的第一個字符的索引。 例如:
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
Python是如此可預測:
>>> string = 'This + is + a + string'
>>> string.find('+',7)
10
結帳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.
也適用於str.index
除了在找不到子字符串時會raise ValueError
而不是-1
。
您可以使用:
start_index = 7
next_index = string.index('+', start_index)
string.find('+', 7)
閱讀文檔 。
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
for i in range(index, len(string)):
if string[i] == char:
print(i)
上面的代碼將從你提供index
的索引循環到字符串len(string)
的長度。 然后,如果字符串的索引等於您要查找的字符char
,那么它將打印索引。
你可以將它放在一個函數中並傳入,字符串,索引和字符,然后返回i。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.