Question

我正在尝试编写一个正则表达式来从单词的开头处删除空格，而不是在单词后面的单个空格中删除空格。

使用RegExp：

var re = new RegExp(/^([a-zA-Z0-9]+\s?)*$/);

测试Exapmle：

1) test[space]ing - Should be allowed 
2) testing - Should be allowed 
3) [space]testing - Should be allowed but have to trim the space at the first
4) testing[space] - Should be allowed but have to trim the space at the last 
5) testing[space][space] - should be allowed but have to trim the space at the last  
6) test[space][space]ing - one space should be allowed but the remaining spaces have to be trimmed.

知道如何使用正则表达式实现这一目标吗？

编辑：

我有这个，

 var regExp = /^(\w+\s?)*\s*$/;
if(regExp.test($('#FirstName').val())){
                    $('#FirstName').val().replace(/\s+$/, '');
                }else{
                    var elm = $('#FirstName'),
                    msg = 'First Name must consist of letters with no spaces';
                    return false;
                }

Answer 1

使用捕获组：

var re = /^\s+|\s+$|(\s)\s+/g;
'test ing'.replace(re, '$1')   // => 'test ing'
'testing'.replace(re, '$1')    // => 'testing'
' testing'.replace(re, '$1')   // => 'testing'
'testing '.replace(re, '$1')   // => 'testing'
'testing  '.replace(re, '$1')  // => 'testing'
'test  ing'.replace(re, '$1')  // => 'test ing'

Answer 2

我可能会懒得保持简单并使用两个单独的RE：

// Collapse any multiple spaces into one - handles cases 5 & 6
str.replace(/ {2,}/, ' ');

// Trim any leading space
str.replace(/^ /, '');

或者，作为一个声明：

var result = str.replace(/ {2,}/, ' ').replace(/^ ?/, '');

Answer 3

这个怎么样：

replace(/^ | $|( ) +/, $1)?

正则表达式，在第一个/最后一个名称验证中只允许一个空格

3 个答案: