Javascript 正则使用第一篇

replace()

参数说明

• @param match
  The matched substring. (Corresponds to $&.)

• @param p1

• @param p2

• @param p3
  The nth parenthesized submatch string,
  provided the first argument to replace was a RegExp object.
  (Corresponds to $1, $2, etc. above.) For example,
  if /(\a+)(\b+)/, was given, p1 is the match for \a+, and p2 for \b+.

• @param offset
  The offset of the matched substring within the total string being examined. (For example,
  if the total string was "abcd",
  and the matched substring was "bc",
  then this argument will be 1.)

• @param string
  The total string being examined.

• @returns {*|string}

function replacer(match, p1, p2, p3, offset, string) {     
    console.log('match: ' + match);
    console.log('string: ' + string);
    //p1 is nondigits, p2 digits, and p3 non-alphanumerics
    console.log('p1: ' + p1);
    console.log('p2: ' + p2);
    console.log('p3: ' + p3);   
    //此处赋值，为了更好的观察p1,p3的值，位置
    p1 = 1;
    p3 = 3;    
   return [p1, p2, p3].join(' - ');
}
newString = "111abc12345#$*%".replace(/([^\d]*)(\d*)([^\w]*)/, replacer);
console.log(newString);

运行结果：

 * match: 111
 * string: 111abc12345#$*%
 * p1:
 * p2: 111
 * p3:
 * 1 - 111 - 3abc12345#$*%

function replacer2(match, p1, p2, p3, offset, string) {
    console.log('match: ' + match);
    console.log('string: ' + string);
    // p1 is nondigits, p2 digits, and p3 non-alphanumerics
    console.log('p1: ' + p1);
    console.log('p2: ' + p2);
    console.log('p3: ' + p3);
    return [p1, p2, p3].join(' - ');
}
newString2 = "abc12345xxx#$*%".replace(/([^\d]*)(\d*)([^\w]*)/, replacer2);
console.log(newString2);

运行结果：

 * match: abc12345
 * string: abc12345xxx#$*%
 * p1: abc
 * p2: 12345
 * p3:
 * abc - 12345 - xxx#$*%

function replacer3(match, p1, p2, p3, offset, string) {
    console.log('match: ' + match);
    console.log('string: ' + string);
    // p1 is nondigits, p2 digits, and p3 non-alphanumerics
    console.log('p1: ' + p1);
    console.log('p2: ' + p2);
    console.log('p3: ' + p3);
    return [p1, p2, p3].join(' - ');
}
newString3 = "1111abc12345xxx#$*%2392039abc12345xxx#$*%".replace(/([^\d]*)(\d*)([^\w]*)/g, replacer3);
console.log(newString3);

运行结果：

 * 第一次匹配

 * match: 1111 
 * string: 1111abc12345xxx#$*%2392039abc12345xxx#$*%
 * p1:
 * p2: 1111
 * p3:

 * 第二次匹配

 * match: abc12345
 * string: 1111abc12345xxx#$*%2392039abc12345xxx#$*%
 * p1: abc
 * p2: 12345
 * p3:


 * 第三次匹配

 * match: xxx#$*%2392039
 * string: 1111abc12345xxx#$*%2392039abc12345xxx#$*%
 * p1: xxx#$*%
 * p2: 2392039
 * p3:


 * 第四次匹配

 * match: abc12345
 * string: 1111abc12345xxx#$*%2392039abc12345xxx#$*%
 * p1: abc
 * p2: 12345
 * p3:

 * 第五次匹配

 * match: xxx#$*%
 * string: 1111abc12345xxx#$*%2392039abc12345xxx#$*%
 * p1: xxx#$*%
 * p2:
 * p3:

 * 第六次匹配

 * match:
 * string: 1111abc12345xxx#$*%2392039abc12345xxx#$*%
 * p1:
 * p2:
 * p3:
 * - 1111 - abc - 12345 - xxx#$*% - 2392039 - abc - 12345 -     xxx#$*% -  -  -  -

match()

function match1() {
    var str = "For more information, see Chapter 3.4.5.1",
        re = /(chapter \d+(\.\d)*)/i,
        found = str.match(re);

    console.dir(found);
}

match1();

运行结果：

 * Array[3]
 * 0: "Chapter 3.4.5.1"
 * 1: "Chapter 3.4.5.1"
 * 2: ".1"
 * index: 26
 * input: "For more information, see Chapter 3.4.5.1"
 * length: 3
 *
 * [input]:
 *         which contains the original string that was parsed
 * [0]:
 *     the first match
 * [1]:
 *     the first value remembered from (Chapter \d+(\.\d)*).
 * [2]:
 *     ".1" is the last value remembered from (\.\d).
 * ---------------------------------------------------
 */

function match2() {
    var str = "For more information, see Chapter 3.4.5.1",
        re = /(chapter \d+(\.\d)*)/gi,
        found = str.match(re);

    console.dir(found);
}

match2();

运行结果：

 * Array[1]
 * 0: "Chapter 3.4.5.1"
 * length: 1
 *
 * 如果使用了全局匹配g, 则只显示匹配到的全部字符串。
 * 也没有input属性

function match3() {
    var str = "[e-mail]",
        re = /(.*)@(.*)\.(.*)/,
        found = str.match(re);

    console.dir(found);
}

match3();

运行结果：

 * Array[4]
 * 0: "[e-mail]"
 * 1: "qbylucky"
 * 2: "gmail"
 * 3: "com"
 * index: 0
 * input: "[e-mail]"
 * length: 4

function match4() {
    var str = "[e-mail]",
        re = /(.*)@(.*)\.(.*)/g,
        found = str.match(re);

    console.dir(found);
}

match4();

运行结果：

 * Array[1]
 * 0: "[e-mail]"
 * length: 1