Python - 定制pattern的string模板(template) 具体解释
定制pattern的string模板(template) 具体解释
本文地址: http://blog.csdn.net/caroline_wendy/article/details/28625179
string.Template的pattern是一个正則表達式, 能够通过覆盖pattern属性, 定义新的正則表達式.
如: 使用新的定界符"{{", 把{{var}}作为变量语法.
代码:
# -*- coding: utf-8 -*- ''' Created on 2014.6.5 @author: Administrator @edition : python 3.3.0, eclipse pydev ''' import string t = string.Template('$var') print(t.pattern.pattern) class MyTemplate(string.Template): delimiter = '{{' pattern = r''' \{\{(?: (?P<escaped>\{\{) | # Escape sequence of two delimiters (?
P<named>[_a-z][_a-z0-9]*)\}\} | # delimiter and a Python identifier {(?P<braced>[_a-z][_a-z0-9]*)}\}\} | # delimiter and a braced identifier (?P<invalid>) # Other ill-formed delimiter exprs ) ''' t2 = MyTemplate(''' {{{{ {{var}} ''') print('MATCHES: ', t2.pattern.findall(t2.template)) print('SUBSTITUTED: ', t2.safe_substitute(var='replacement'))
输出:
\$(?: (?P<escaped>\$) | # Escape sequence of two delimiters (?P<named>[_a-z][_a-z0-9]*) | # delimiter and a Python identifier {(?P<braced>[_a-z][_a-z0-9]*)} | # delimiter and a braced identifier (?P<invalid>) # Other ill-formed delimiter exprs ) MATCHES: [('{{', '', '', ''), ('', 'var', '', '')] SUBSTITUTED: {{ replacement