Python程序查找字符串中子字符串出现的次数

给定一个单词列表，提取这些单词在字符串中出现的所有索引。

Input : test_str = ‘geeksforgeeks is best for geeks and cs’, test_list = [“best”, “geeks”] 
Output : [2, 4] 
Explanation : best and geeks occur at 2nd and 4th index respectively.

Input : test_str = ‘geeksforgeeks is best for geeks and cs’, test_list = [“best”, “geeks”, “is”] 
Output : [1, 2, 4] 
Explanation : is, best and geeks occur at 1st, 2nd and 4th index respectively. 
 

方法 #1：使用列表理解 + split() + index()

在这里，我们使用 split() 执行从句子中获取单词的任务，然后使用 index() 将字符串列表中的单词匹配到提取的字符串。

Python3

# Python3 code to demonstrate working of 
# Word occurrence positions in String
# Using list comprehension + split() + index()
  
# initializing string
test_str = 'geeksforgeeks is best for geeks and cs'
  
# printing original string
print("The original string is : " + str(test_str))
  
# initializing list 
test_list = ["best", "geeks", "cs"]
  
# using index() to get indices,
# list comprehension used to offer one liner
res = [test_str.split().index(ele) 
       for ele in test_str.split() if ele in test_list]
          
# printing result 
print("The indices list : " + str(res))

输出

The original string is : geeksforgeeks is best for geeks and cs
The indices list : [2, 4, 6]

方法 #2：使用列表推导 + enumerate() + split()

这是可以执行此任务的另一种方式。在这个获取索引的任务中，使用 enumerate() 来完成。

蟒蛇3

# Python3 code to demonstrate working of 
# Word occurrence positions in String
# Using list comprehension + enumerate() + split()
  
# initializing string
test_str = 'geeksforgeeks is best for geeks and cs'
  
# printing original string
print("The original string is : " + str(test_str))
  
# initializing list 
test_list = ["best", "geeks", "cs"]
  
# using enumerate() to get indices,
# list comprehension used to offer one liner
res = [idx for idx, ele in enumerate(test_str.split()) if ele in test_list]
          
# printing result 
print("The indices list : " + str(res))

输出

The original string is : geeksforgeeks is best for geeks and cs
The indices list : [2, 4, 6]