1 unescape

try:
  from HTMLParser import HTMLParser   # Python2
except ImportError:
  from html.parser import HTMLParser  # Python3
html_parser = HTMLParser()
s = '1<2'
print(html_parser.unescape(s))
# 1<2

2 escape

import cgi
s = '1<2'
print(cgi.escape(s))
# 1&lt;2

对照表

• https://www.runoob.com/tags/html-symbols.html
• http://tool.oschina.net/commons?type=2