string.count(str)
时间: 2024-05-20 18:16:34 浏览: 14
This method is used to count the number of occurrences of a substring within a string. It takes a single argument 'str' which specifies the substring to be counted.
Syntax:
string.count(str)
Example:
string = "Python is a popular programming language"
count = string.count('p')
print(count)
Output:
3
In the above example, the count method is used to count the number of occurrences of the letter 'p' in the string. The output is 3 because 'p' occurs three times in the string.
相关问题
str.count()
str.count() 是 Python 中字符串对象的一个方法,用于统计字符串中某个子串出现的次数。该方法的语法为:
```python
str.count(sub[, start[, end]])
```
其中,`str` 是要进行计数的字符串,`sub` 是要计数的子串,`start` 和 `end` 是可选参数,用于指定计数的起始和结束位置。如果不指定 `start` 和 `end`,则默认计数整个字符串中出现的子串数量。
例如:
```python
string = "hello world"
count = string.count("l")
print(count) # 输出 3
```
这段代码中,`count` 的值为 3,因为字符串 `"hello world"` 中字符 `"l"` 出现了 3 次。
string.prototype
There is a typo in the question. The correct method name is `String.prototype`.
`String.prototype` is a property that represents the prototype for the String constructor. It allows you to add new methods and properties to all string objects.
For example, you can add a new method called `countOccurrences` to the `String.prototype` like this:
```javascript
String.prototype.countOccurrences = function(substring) {
let count = 0;
let index = this.indexOf(substring);
while (index !== -1) {
count++;
index = this.indexOf(substring, index + 1);
}
return count;
}
let str = "hello world";
console.log(str.countOccurrences("l")); // output: 3
```
This adds a new method `countOccurrences` to all string objects, which counts the number of occurrences of a substring within the string.