使用javascript编写正则表达式以从字符串中去除st，nd，rd或th之前的空格

Question

我有以下字符串 原始字符串

"1 st-May-2014"                
"2 nd-May-2014"                 
"3 rd-May-2014"                 
"14 th-May-2014" 

输出

"1st-May-2014"  
"2nd-May-2014"
"3rd-May-2014"
"14th-May-2014"

现在我想在JavaScript中使用RegEx从上面的字符串中移除 st，nd，rd和th 之前的空格。

Answer 1

这是我的建议：

result = subject.replace(/\s+(?=(?:st|nd|rd|th)\b)/g, "");

<强>解释

\s+              # Match whitespace
(?=              # if the following text can be matched after it:
 (?:st|nd|rd|th) # one of the four "words"
 \b              # that end there (so as not to match "4 stones")
)                # End of lookahead assertion

Answer 2

我想，你需要这个：

result = subject.replace(/^(\d+)\s+(.*)$/gm,"$1$2");