Question

我想使用正则表达式将子字符串保存到javascript变量，除非有不同/更简单的方法。例如，我有这样的链接： http://www.youtube.com/watch?v=sEHN4t29oXY&feature=related

我想只获得sEHN4t29oXY＆amp; feature =相关所以我想我必须检查出现的第一个等号然后将该字符串的其余部分保存到变量中..请帮忙，谢谢

Answer 1

高效：

variable = variable.substring(variable.indexOf('?v=')+3) // First occurence of ?v=

正则表达式：

variable = variable.replace(/.*\?v=/, '') // Replace last occurrence of ?v= and any characters before it (except \r or \n) with nothing. ? has special meaning, that is why the \ is required
variable = variable.replace(/.*?\?v=/, '') // Variation to replace first occurrence.

Answer 2

像这样：

var match = /\?v=(.+)/.exec(link)[1];

Answer 3

不是正则表达式，而是简单，因为第一个url部分是静态的，有23个符号长度

'http://www.youtube.com/watch?v=sEHN4t29oXY&feature=related'.substr(23)

哦，我犯了一个错误，他想要另一部分，所以实际的代码看起来像是：

'http://www.youtube.com/watch?v=sEHN4t29oXY&feature=related'.substr(31)

Answer 4

我认为从查询字符串中获取参数的最简单方法是使用以下代码：

var u = new URI('http://www.youtube.com/watch?v=sEHN4t29oXY&feature=related');
u.getQuery('v') //sEHN4t29oXY
u.getQuery('feature') //related

现在，有人应该像我这样的评论大喊大叫：

JavaScript中没有URI对象，你不能这样做！11one

那个人会是对的，所以你走了：

/**
 * URI.js by zzzzBov
 */
(function (w) {
  "use strict";
  var URI = function (str) {
    if (!this) {
      return new URI(str);
    }
    if (!str) {
      str = window.location.toString();
    }
    var parts, uriRegEx, hostParts;
    //http://labs.apache.org/webarch/uri/rfc/rfc3986.html#regexp
    uriRegEx = /^(([^:\/?#]+):)?(\/\/([^\/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?/;
    str = str.toString();
    parts = uriRegEx.exec(str);
    this.protocol = parts[1] || '';
    this.host = parts[4] || '';
    this.pathname = parts[5] || '';
    this.search = parts[6] || '';
    this.hash = parts[8] || '';
    //logic to break host into hostname:port
    hostParts = this.host.split(':');
    this.hostname = hostParts[0] || '';
    this.port = hostParts[1] || '';
  };
  URI.prototype = {
    getQuery: function (i) {
      var o;
      o = URI.parseQueryString(this.search);
      return i === undefined ? o : o[i];
    },
    setQuery: function (val) {
      var s;
      s = URI.buildQueryString(val);
      this.search = s.length ? '?' + s : s;
    },
    toString: function () {
      return this.protocol + '//' + this.host + this.pathname + this.search + this.hash;
    }
  };
  URI.parseQueryString = function (str) {
    var obj, vars, i, l, data, rawKey, rawVal, key, val;
    obj = {};
    if (!str) {
      return obj;
    }
    //make sure it's a string
    str = str.toString();
    if (!str.length || str === '?') {
      return obj;
    }
    //remove `?` if it is the first char
    if (str[0] === '?') {
      str = str.substr(1);
    }
    vars = str.split('&');
    for (i = 0, l = vars.length; i < l; i += 1) {
      data = vars[i].split('=');
      rawKey = data[0];
      rawVal = data.length > 1 ? data[1] : '';
      //if there's a key, add a value
      if (rawKey) {
        key = URI.decode(rawKey);
        val = URI.decode(rawVal);
        //check if obj[key] is set
        if (obj.hasOwnProperty(key)) {
          if (typeof obj[key] === 'string') {
            //if it's a string turn it to an array
            obj[key] = [ obj[key], val ];
          } else {
            //it's an array, push
            obj[key].push(val);
          }
        } else {
          obj[key] = val;
        }
      }
    }
    return obj;
  };
  URI.buildQueryString = function (obj) {
    var arr, key, val, i;
    function build(key, value) {
      var eKey, eValue;
      eKey = URI.encode(key);
      eValue = URI.encode(value);
      if (eValue) {
        arr.push(eKey + '=' + eValue);
      } else {
        arr.push(eKey);
      }
    }
    arr = [];
    for (key in obj) {
      if (obj.hasOwnProperty(key)) {
        val = obj[key];
        //isArray check
        if (Object.prototype.toString.call(val) === '[object Array]') {
          for (i in  val) {
            if (val.hasOwnProperty(i)) {
              build(key, val[i]);
            }
          }
        } else {
          build(key, val);
        }
      }
    }
    return arr.join('&');
  };
  URI.decode = decodeURIComponent;
  URI.encode = encodeURIComponent;
  w.URI = URI;
}(window));

如何在给定字符后选择子字符串

4 个答案: