<p>这是您的正则表达式,当前分组为:<br/>
<a href="http://www.regexformat.com" rel="nofollow">Formatted and tested:</a></p>
<pre><code> a=
( # (1 start)
[-+]?
( \d* [.] )? # (2)
\d+
) # (1 end)
\ b=
( # (3 start)
[-+]?
( \d* [.] )? # (4)
\d+
) # (3 end)
\ c=
( # (5 start)
[-+]?
( \d* [.] )? # (6)
\d+
) # (5 end)
</code></pre>
<p>输出:</p>
^{pr2}$
<p>您不需要<em>可选的</em>捕获子组。<br/>
在将它们转换为<em>簇组之后:</p>
<pre><code> # a=([-+]?(?:\d*[.])?\d+) b=([-+]?(?:\d*[.])?\d+) c=([-+]?(?:\d*[.])?\d+)
a=
( # (1 start)
[-+]?
(?: \d* [.] )?
\d+
) # (1 end)
\ b=
( # (2 start)
[-+]?
(?: \d* [.] )?
\d+
) # (2 end)
\ c=
( # (3 start)
[-+]?
(?: \d* [.] )?
\d+
) # (3 end)
</code></pre>
<p>输出:</p>
<pre><code> ** Grp 0 - ( pos 0 , len 27 )
a=2323.232323 b=23.23 c=112
** Grp 1 - ( pos 2 , len 11 )
2323.232323
** Grp 2 - ( pos 16 , len 5 )
23.23
** Grp 3 - ( pos 24 , len 3 )
112
</code></pre>