括号内的Javascript Reg Exp号码(Javascript Reg Exp number in brackets) if (!$is.IE5) { v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])[1]; }

[1]在这个reg表达式中意味着什么？

if (!$is.IE5) { v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])[1]; }

What does [1] mean in this reg expression??

最满意答案

答案是对数组的尊重 。

v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])[1];

将函数[1]应用于函数结果，得到第一个匹配的组（组用圆括号()分隔）。

所以v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])的第一组匹配(ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[]) 。

请注意末尾的||[] ，它允许不匹配不会给出错误。

第一组匹配是([\\d.]+)组，由于(?:...)不匹配的组结构，第一个括号不会被存储。

It is an array deference on the answer.

v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])[1];

The deference [1] is applied to the function result, to get the first matched group (groups are delimited with parentheses ()).

So v = the first group match of (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[]).

Note the ||[] at the end which allows for no matches to not give an error.

This first group match is the ([\\d.]+) group, the first parentheses is not stored due to the (?:...) non-matching group construct.

括号内的Javascript Reg Exp号码(Javascript Reg Exp number in brackets) if (!$is.IE5) { v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])[1]; }

[1]在这个reg表达式中意味着什么？

if (!$is.IE5) { v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])[1]; }

What does [1] mean in this reg expression??

最满意答案

答案是对数组的尊重 。

v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])[1];

将函数[1]应用于函数结果，得到第一个匹配的组（组用圆括号()分隔）。

所以v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])的第一组匹配(ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[]) 。

请注意末尾的||[] ，它允许不匹配不会给出错误。

第一组匹配是([\\d.]+)组，由于(?:...)不匹配的组结构，第一个括号不会被存储。

It is an array deference on the answer.

v = (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[])[1];

The deference [1] is applied to the function result, to get the first matched group (groups are delimited with parentheses ()).

So v = the first group match of (ua.toLowerCase().match(new RegExp(".+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)"))||[]).

Note the ||[] at the end which allows for no matches to not give an error.

This first group match is the ([\\d.]+) group, the first parentheses is not stored due to the (?:...) non-matching group construct.