python - 如何在不使用起始索引或范围作为参数的情况下找到一个单词在句子中第二次或第三次出现的索引号？（Python）

Question

我有以下句子-

Sammy likes to swim in the ocean, likes to spin servers, and likes to smile.

我想找到单词第二次出现的起始索引号likes

但我不想使用起始索引号或范围作为str.find()函数的参数。

如果可能的话，我想避免正则表达式，因为初学者很难理解。

str.find()注意：使用功能不是强制性的。我只想知道是否可以不给出起始索引或范围作为参数。

Answer 1

使用第二个捕获组的正则表达式和start和：end

import re
s = 'Sammy likes to swim in the ocean, likes to spin servers, and likes to smile.'
m = re.match(r'.*(likes).*(likes).*', s)
m.start(2)  # start of second capturing group
# 61
m.end(2)  # end of second capturing group
# 66
s[m.start(2), m.end(2)]
# 'likes'

Answer 2

使用正则表达式怎么样？

import re

string = 'Sammy likes to swim in the ocean, likes to spin servers, and likes to smile.'
pattern = 'likes'
likes = [(m.start(0), m.end(0)) for m in re.finditer(pattern, string)]
# [(6, 11), (34, 39), (61, 66)]

likes[1][0] 有你想要的

Answer 3

正常循环方法：

string = "Sammy likes to swim in the ocean, likes to spin servers, and likes to smile."
word = "likes"
indexes = []
for i in range(len(string)):
    if string[i:i+len(word)] == word:
        indexes.append(i)
print(indexes[1]) # Second location, outputs: 34

列表理解：

[i for i in range(len(string)) if string[i:i+len(word)] == word][1] # Outputs: 34