擅长:python、mysql、java
<p>开头的问号是<code>nothing to repeat</code>错误的原因。你知道吗</p>
<pre><code>>>> import re
>>> re.compile(r'?')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/mj/Development/venvs/stackoverflow-2.7/lib/python2.7/re.py", line 190, in compile
return _compile(pattern, flags)
File "/Users/mj/Development/venvs/stackoverflow-2.7/lib/python2.7/re.py", line 242, in _compile
raise error, v # invalid expression
sre_constants.error: nothing to repeat
</code></pre>
<p>匹配美元加号和点:</p>
<pre><code>r'\$[\d.]+'
</code></pre>
<p>演示:</p>
<pre><code>>>> re.search(r'\$[\d.]+', 'blah blah blah (blah $23.32 blah) blah blac (blah)').group()
'$23.32'
</code></pre>