欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  IT编程

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

程序员文章站 2024-02-26 20:36:34
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...

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:

# -*- 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 

感谢阅读,希望能帮助到大家,谢谢大家对本站的支持!