Javascript正則表達式，它與被其他字符污染的小數相匹配

Question

我試圖匹配以下示例中的第一組數字。

some stuff (6 out of 10 as a rating) 

需要返回6只

some stuff (2.3 out of 10 as a rating)  

需要返回2.3

some stuff (10 out of 10 as a rating) 

需要返回10

此外，有時串將不具有數

some stuff but nothing else 

Answer 1

var match = /\d+(\.\d+)?/.exec("some stuff (10 out of 10 as a rating)"); 
alert(match[0]); 

• \d匹配任何numner，0-9
• +指1個或多個
• \.相匹配的。
• ?指0或1

所以整體就意味着任何數量的數字（0-9）任選地接着，小數點隨後用1個或多個數字。

作爲一個功能：

var getFirstNumber = function(input){ 
    var match = /\d+(\.\d+)?/.exec(input); 
    return match[0]; 
}; 

Answer 2

你可以試試這個'some stuff (2.3 out of 10 as a rating)'.match(/\D*(\d\.?(\d)*)/)[1]