[regex] 更多的正则表达式使用例子

#匹配URL

            //不考虑注入
            var a = /^(?:([A-Za-z]+):)?(\/{0,2})([0-9.\-A-Za-z]+)(?::(\d+))?(?:\/([^?#]*))?(?:\?([^#]*))?(?:#(.*))?$/;
            var b = 'http://www.ok.com:80/goodbye?q#fragment';
            var c = a.exec(b);
            console.log(c);
            var names = ['url', 'scheme', 'slash', 'host', 'port', 'path', 'query', 'hash'];
            var blanks = '      ';
            var i;
            for (i = 0; i < names.length; i += 1) {
                console.log(names[i] + ':' + blanks + c[i]);
            }
            //url:     http://www.ok.com:80/goodbye?q#fragment
            //scheme:  http
            //slash:   //
            //host:    www.ok.com
            //port:    80
            //path:    goodbye
            //query:   q
            //hash:    fragment

#

            //匹配数字
            var parse_number = /^-?\d+(?:\.\d*)?(?:e[+\-]?\d+)?$/i;
            var test = function(num) {
                console.log(parse_number.test(num));
            };
            test('1'); // true
            test('number'); // false
            test('98.6'); // true
            test('132.21.86.100'); // false
            test('123.45E-67'); // true
            test('123.45D-67'); // false

#转换成整数

filterInt = function (value) {
  if(/^(\-|\+)?([0-9]+|Infinity)$/.test(value))
    return Number(value);
  return NaN;
}

 

            //寻找重复的单词
            var doubled_words = /([A-Za-z\u00C0-\u1FFF\u2800-\uFFFD]+)\s+\1/gi;
            //匹配非ASCII特殊字符的字符
            /[^!-\/:-@\[-`{-˜]/
            //匹配成对的引号
            /(['"])[^'"]*\1/
            //将英文引号转换为中文引号，且不改变引号里的内容
            var quote = /"([^"]*)"/g;
            str.replace(quote,'“$1”');
            //也是匹配URL
            /(\w+):\/\/([\w.]+)\/(\S*)/;
            //split 以,分割，允许有空格
            "1,  2,  3, 4,  5".split(/\s*,\s*/);

 #

所有空格符

/\s+/g

所有非空格符

/[^\s]+/g

所有数字

/\d+/g

所有非数字

/[^\d]+/g

匹配首尾的  -

/^-|-$/g

匹配左右两侧空白符

/^\s+|\s+$/g

匹配这几个单词

 /\bsome|foo|the|by|for|poor\b/ig

匹配非字母和数字

/[^a-z0-9]+/ig

匹配第一个‘bat’或‘cat’

/[bc]at/

匹配 000-00-0000

/\d{3}-\d{2}-\d{4}/

 

#

            //字符转换
            function DNAStrand(dna) {
                var pairs = {
                    A: 'T',
                    T: 'A',
                    C: 'G',
                    G: 'C',
                }
                return dna.replace(/./g, function(c) {
                    return pairs[c]
                })
            }
            //检测成对的括号
            function isBalanced(s) {
                s = s.replace(/[^()]+/g, '');
                var m = /\(\)/,
                    r = /\(\)/g;
                while (m.test(s)) {
                    s = s.replace(r, '');
                }
                return s === '';
            }

#密码匹配

            //密码匹配，至少有一个大写字母，小写字母，数字，字符串大于6位
            function validate(password) {
                return /^[A-Za-z0-9]{6,}$/.test(password) &&
                    /[A-Z]+/.test(password) &&
                    /[a-z]+/.test(password) &&
                    /[0-9]+/.test(password);
            }

            function validate(password) {
                return /^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])[a-zA-Z0-9]{6,}$/.test(password);
            }
            console.log(validate('djI38D55'));
            console.log(validate('a2.d412'));
            console.log(validate('JHD5FJ53'));
            console.log(validate('123'));
            console.log(validate('!123'));

 #

//匹配重复字母
function duplicateCount(text) {
    return (text.toLowerCase().split('').sort().join('').match(/([^])\1+/g) || []).length;
}

function duplicateCount(text) {
    return (text.toLowerCase().match(/(.)(?=.*\1)/g) || []).filter(function(c, i, letters) {
        return letters.indexOf(c) === i
    }).length
}

 #

        //求数字的底数和指数
            var isPP = function(n) {
                var temp = 0;
                if (/^(\d+\.+\d+|[0-3])$/.test('' + n)) {
                    return null;
                }
                for (var i = 2; i < n; i++) {
                    if (Math.pow(i, 2) > n) {
                        return null;
                    }
                    for (var j = 2; j < n; j++) {
                        temp = Math.pow(i, j);
                        if (temp > n) {
                            break;
                        }
                        if (temp === n) {
                            return [i, j];
                        }
                    }
                }
            }
            console.log(isPP(100));
            console.log(isPP(32));
            console.log(isPP(27));
            console.log(isPP(8));
            console.log(isPP(9));
            console.log(isPP(5));
            console.log(isPP(4));
            console.log(isPP(4.1));
            console.log(isPP(1));
            console.log(isPP(2));
            console.log(isPP(3));
            console.log(isPP(0));

 #简单的字母匹配查字典

            function autocomplete(input, dictionary) {
                var a = input.toLowerCase().replace(/[^a-z]/g, '');
                var b = [];
                var reg = new RegExp('^'+a+'.*$');
                for (var i = 0; i < dictionary.length; i++) {
                    if (dictionary[i].toLowerCase().search(reg) > -1) {
                        b.push(dictionary[i]);
                    }
                    if (b.length == 5) {
                        return b;
                    }
                }
                return b;
            }



function autocomplete(input, dictionary){
  var r = new RegExp('^' + input.replace(/[^a-z]/gi,''), 'i');
  return dictionary.filter(function(w){ return r.test(w); }).slice(0, 5);
}

console.log(autocomplete('ai', ['airplane', 'airport', 'apple', 'ball']));

 #

            function dirReduc(arr) {
                var reg = /NORTHSOUTH|SOUTHNORTH|EASTWEST|WESTEAST/,
                    a = arr.join('');
                while (reg.test(a)) {
                    a = a.replace(reg, '');
                }
                return a.match(/NORTH|SOUTH|EAST|WEST/g) || [];
            }


dirReduc(["NORTH", "SOUTH", "SOUTH", "EAST", "WEST", "NORTH", "WEST"])//["WEST"]
dirReduc(["NORTH", "WEST", "SOUTH", "EAST"])// ["NORTH", "WEST", "SOUTH", "EAST"]
dirReduc(["NORTH", "SOUTH", "EAST", "WEST", "EAST", "WEST"])//[]

 #

var Mod4 = /^([^\d]*\[(\+|-)*(?:0)*\d+\][^\d]*)+$/;

var Mod4 = /\[[-+]?(?:[048]|\d*[02468][048]|\d*[13579][26])]/;

var Mod4 = /\[[-+]?([048]|\d*([02468]+[048]|[13579][26]))\]/;

Mod4.test(str)


            "[+05620]" // 5620 is divisible by 4 (valid)
            "[+05621]" // 5621 is not divisible by 4 (invalid)
            "[-55622]" // -55622 is not divisible by 4 (invalid)
            "[005623]" // 5623 invalid
            "[005624]" // 5624 valid
            "[-05628]" // valid
            "[005632]" // valid
            "[555636]" // valid
            "[+05640]" // valid
            "[005600]" // valid
            "the beginning [0] ... [invalid] numb[3]rs ... the end" // 0 is valid
            "No, [2014] isn't a multiple of 4..." // 2014 is invalid
            "...may be [+002016] will be." // 2016 is valid


            // invalid
                "[+05621]",
                "[-55622]",
                "[005623]",
                "[~24]",
                "[8.04]",
                "No, [2014] isn't a multiple of 4..."

 #文件路径简单处理

            function imageFile(url, wid, hei) {
                var width = wid || 100;
                var height = hei || 100;
                return (url + '').replace(/(\w+)\.(\w+)$/g, '$1' + '_' + width + '_' + height + '.$2');
            }

 

#格式化数字

            var a = 9999999999;
            var b = (a + '').replace(/\d{1,3}(?=(\d{3})+$)/g, '$&,');
            console.log(b);
            //99,999,999,999

 

#转化驼峰法

        var foo="get-element-by-id";
        var b = foo.replace(/-([a-z])/g,up);
        function up(match,p1){
            return p1.toUpperCase();
        }

 

#类似模板替换

            function fn(str) {
                this.str = str;
            }
            fn.prototype.format = function() {
                var args = [].slice.call(arguments);
                var i = 0;
                return this.str.replace(/\{\d+\}/g, function(a) {
                    return args[i++] || "";
                });
            }
            var t = new fn('<p><a href="{0}">{1}</a><span>{2}</span></p>');
            console.log(t.format('http://www.alibaba.com', 'Alibaba', 'Welcome'));

 

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