How to intercept string in js

JavaScript is a scripting language widely used in web development. It has powerful string processing capabilities. In JavaScript, intercepting strings is a common operation and can be implemented in many ways. This article will introduce several commonly used methods to intercept strings.

1. Use the substring() method

The substring() method is a function used to intercept strings in JavaScript. It accepts two parameters, the starting position and the ending position. The starting position is the index of the first character of the substring to be intercepted, and the end position is the index of the last character of the substring to be intercepted plus one. The following is an example:

var str = "Hello World";
var subStr = str.substring(0, 5);
console.log(subStr); // 输出 "Hello"

In the above example, we use the substring() method to intercept from index 0 until the end of index 5, and the resulting substring is "Hello".

2. Use the slice() method

The slice() method is also a commonly used string interception method. It is similar to the substring() method and accepts two parameters, the starting position and the ending position. The difference is that the slice() method allows the use of negative numbers as parameters, indicating that the index is calculated from the end of the string. The following is an example:

var str = "Hello World";
var subStr = str.slice(6, 11);
console.log(subStr); // 输出 "World"

In the above example, we use the slice() method to intercept from index 6 until the end of index 11, and the resulting substring is "World".

3. Use the substr() method

The substr() method can also be used to intercept strings. It accepts two parameters, the starting position and the number of characters to be intercepted. The following is an example:

var str = "Hello World";
var subStr = str.substr(6, 5);
console.log(subStr); // 输出 "World"

In the above example, we use the substr() method to intercept starting from index 6, the length of the interception is 5 characters, and the resulting substring is "World".

4. Use the split() method

The split() method can split the string into a string array, and then you can get the required substrings through the index . Here is an example:

var str = "Hello World";
var subStr = str.split(" ")[1];
console.log(subStr); // 输出 "World"

In the above example, we use the split() method to split the string into a string array by spaces, and then get the second element by index, and the resulting substring It's "World".

Summary:

This article introduces several common methods to intercept strings. Use the substring(), slice(), and substr() methods to intercept strings based on the starting and ending positions or the number of characters. In addition, use the split() method to split the string into a string array, and then obtain the required substrings through indexing. According to specific needs, choose the appropriate method to intercept strings, which can better handle string operations. .

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