Python String count() 方法

Python String count()函数是Python编程语言中的一个内置函数，它返回给定字符串中子字符串的出现次数。

Syntax: 

string.count(substring, start=…, end=…)

Parameters: 

• The count() function has one compulsory and two optional parameters. 
  • Mandatory parameter: 
    • substring – string whose count is to be found.
  • Optional Parameters: 
    • start (Optional) – starting index within the string where the search starts. 
    • end (Optional) – ending index within the string where the search ends.

Return Value:

count() method returns an integer that denotes number of times a substring occurs in a given string. 

示例 1：不带可选参数的 count() 方法的实现

Python3

# Python program to demonstrate the use of
# count() method without optional parameters 
  
# string in which occurrence will be checked
string = "geeks for geeks" 
  
# counts the number of times substring occurs in 
# the given string and returns an integer
print(string.count("geeks"))

输出：

2

示例 2：使用可选参数实现 count() 方法

Python3

# Python program to demonstrate the use of
# count() method  using optional parameters
  
# string in which occurrence will be checked
string = "geeks for geeks" 
  
# counts the number of times substring occurs in 
# the given string between index 0 and 5 and returns 
# an integer
print(string.count("geeks", 0, 5))
  
print(string.count("geeks", 0, 15))

输出：

1
2