Python 中开发pattern的string模板(template) 实例详解

时间:2022-09-09 20:51:35

定制pattern的string模板(template) 详解

string.Template的pattern是一个正则表达式, 可以通过覆盖pattern属性, 定义新的正则表达式.

如: 使用新的定界符"{{", 把{{var}}作为变量语法.

代码:

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# -*- 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:

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  \$(?:
   (?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

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原文链接:http://blog.csdn.net/caroline_wendy/article/details/28625179