Python的字符串模板
Python的字符串模板，可以无需记住类型的细节。
subsitute()#严谨模式，在key缺少的情况下会报一个keyError的异常
safe_subsitute()#在key缺少的情况下会原封不动的把字符串输出来
from string import Template
str = Template('to:${to}\ntitle:${title}\ncontext:${context}')
print(str.substitute(to = '[email protected]',title = 'hi',context = "hello world"),'\n')
print(str.safe_substitute(to = '[email protected]',title = 'hi'),'\n')#可以不初始化
print(str.substitute(title = 'hi',context = "hello world"))
Output：
title:hi
context:hello world
title:hi
context:${context}
Traceback (most recent call last):
File "F:\study\ework\Python\src\day2_string.py", line 6, in <module>
print(str.substitute(title = 'hi',context = "hello world"))
File "D:\Python31\lib\string.py", line 156, in substitute
return self.pattern.sub(convert, self.template)
File "D:\Python31\lib\string.py", line 146, in convert
val = mapping[named]
KeyError: 'to'