<p>我猜我们的表达式必须在这里修改,这可能是问题所在,例如,如果我们希望匹配所需的模式,我们将从一个类似以下的表达式开始:</p>
<pre><code>([a-zA-Z0-9]+)\.
</code></pre>
<p>如果我们希望在<code>.</code>之后有1到3个字符,我们可以将其扩展为:</p>
<pre><code>([a-zA-Z0-9]+)\.([a-zA-Z0-9]{1,3})?
</code></pre>
<h3><a href="https://regex101.com/r/0k0Oai/1/" rel="nofollow noreferrer">Demo 1</a></h3>
<h3><a href="https://regex101.com/r/mFhQcV/1/" rel="nofollow noreferrer">Demo 2</a></h3>
<h3>测试</h3>
<pre><code># coding=utf8
# the above tag defines encoding for this document and is for Python 2.x compatibility
import re
regex = r"([a-zA-Z0-9]+)\.([a-zA-Z0-9]{1,3})?"
test_str = ("hotmail.\n"
"living.\n"
"item.\n"
"2.\n"
"4S.\n"
"hotmail.com\n"
"living.org\n"
"item.co\n"
"2.321\n"
"4S.123")
matches = re.finditer(regex, test_str, re.MULTILINE)
for matchNum, match in enumerate(matches, start=1):
print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group()))
for groupNum in range(0, len(match.groups())):
groupNum = groupNum + 1
print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum)))
# Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.
</code></pre>