javascript正则表达式

实例解析如下：
代码如下：

var patt1 = new RegExp("hello");
var patt2 = /world/;


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// test()方法检索字符串中的指定值，返回true或false
var pat = /my/;
var str = "mycode is my code...";
console.log(pat.test(str)); // true


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// exec()方法检索字符串中的指定值。返回值是被找到的值。如果没有发现匹配，则返回null
var pat = /hello/;
console.log(pat.exec("oh hello world"));

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正则表达式类型
常用属性”g”,”i”,分别用于指定全局匹配、区分大小写的匹配

var str = "Visit user";
var patt1 = /User/i;        // 忽略大小写
console.log(str.match(patt1));

var str = "hello xiaoming!I am admin,Xiaoming say hello";
var patt1 = /xiaoming/ig;       // 忽略大小写，全局匹配
console.log(str.match(patt1));

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字符串正则
1.search：字符串查找

var str = "Visit china";
console.log(str.search(/china/));   // 6

var str = "Visit china";
console.log(str.search(/China/ig));  // 6

var str = "china Visit china";
console.log(str.search(/China/ig));  //0 匹配到第一个

2.match：字符串匹配

var str = "1 plus 2 equal 3";
console.log(str.match(/\d+/));
console.log(str.match(/\d+/g));

3：replace:字符串替换

var str = "Hello china!oh I am chinaHHH";
console.log(str.replace(/china/,"test"));

var str = "Hello china!oh I am chinaHHH";
console.log(str.replace(/china/ig,"test"));

console.log(str);

4.字符串分割

var str = "Hello Hunger,oh I am Hunger";
str.split("");

var str = "Hello Hunger,oh I am Hunger";
str.split(/\s+/);