Summary of common methods of js string() (graphic tutorial)

The following is a summary of common methods of js string() that I have compiled for you. Interested students can take a look.

Create a String object, syntax: new String(stringValue), this call will convert the parameter into a string and use it as a String object. In fact, any string constant is a String object, which can be used directly as an object. The difference between this and using new String() to create an object is: the return value of typeof is different, one is "string", the other is "object".
string.indexOf(searchString,position)----Starting from the position (optional) position, search for the position where the first searchSting appears in the string and return it. For example: "hello,jack".indexOf("hello") will return 0;
"abcabc".indexOf("a",1) will return 4; (counting from 0)
string.lastIndexOf (searchString, position)--------Starting from the position (optional) position, search for the position where the last searchString appears in the string and return it. For example: "abcabc".lastIndexOf("b") will return 4
string.charAt(pos)-------returns the character at position pos in the string. For example: "abc".charAt(1) returns "b"
stirng.charCodeAt(pos)------returns the character code at position pos in the string. For ASCII characters, this returns their ASCII code. For example: "abc".charCodeAt(0) returns 97, which represents the ASCII code of character "a".
string.slice(start,end)--------Returns the substring whose starting position is start and the ending position is end (excluding end) in the string
string.split(separator ,linmit)------Cut the string into multiple substrings using separator as the separator, and return them as an array. linmit (optional) indicates the maximum length of the array, and the excess part will be discarded. The separator delimiter is not included in any substring. If separator is an empty string, an array consisting of the character sequence in the string is returned. If the split method does not take any parameters, it returns an array containing only the string itself and only one element.
string.split(separator,linmit)-------For example: "a1,b1,c1".split(",") will return ["a1","b1","c1"];
"a,b,c".split(",",2) will return ["a","b"];
"a,b,c".split("") will return [ "a",",","b",",","c"];
"ab,c".split() will return ["ab,c"]
string.substr(start ,length)--------Returns the substring whose starting position is start and whose length is length in the string. For example: "abcdefg".substr(1,3) will return "bcd";
string.substring(start,end)------The starting position in the returned string is start and the end position is end ( substring including end). The only difference between this method and the slice method is that slice does not accept negative parameters. Replace and match strings
(1)replace(searchValue,replaceValue) method
This method replaces the first searchValue subcharacter that appears in the string String is replaced with replaceValue and the new string is returned. The original string is not affected.

例如：var str1="aaaa";
var str2=str1.replace("a","b");
alert(str2);//输出"baaa"
alert(str1);//输出"aaaa"

As can be seen from the above code, only one instance can be replaced using the replace function. If you want to replace multiple instances, you need to use regular expressions. For example, str.replace(/a/g,"b") can replace "aaaa" with "bbbb".
(2) match(reExp) method
Search for all substrings matching the regExp regular expression from the string and return them as an array. Using the conversion rules from object type to Boolean type, you can also determine whether a string matches the regular expression represented by regExp.

例如：var strInput=prompt("请输入一个数字：",0);
while(!strInput.match(/\d+/)){
         strInput=prompt("请输入一个数字：",0);
}

(3)search(regExp) method
Search the first substring matching the regExp regular expression from the string and return its index position . For example: var str="aabcabcabc";

alert(str.search(/abc/g));//显示“１”

（４）String 对象的大小写转换

var str="abc";
str.toLowerCase()//转化小写
str.toUpperCase()//转化大写

（５）String 对象的连接

var str="abc";
var str2=str.concact("def","ghi");
alert(str2);//将输出"abcdefghi"

上面是我整理给大家的js string()常用方法总结，希望今后会对大家有帮助。

相关文章：

在vue项目中使用sass的配置方法_vue.js

动态操作js/css文件有哪些方法

nodejs连接mysql数据库步骤详解

The above is the detailed content of Summary of common methods of js string() (graphic tutorial). For more information, please follow other related articles on the PHP Chinese website!