我不确定你是如何让它发挥作用的。在linux上,在python 3.4.3中(我想我可以在2.7的某些版本上使用它)我需要使 tpl 成为一个字符串
tpl = '''
"unaltered": "{{foo}}",
"replaced": "{{test}}"
'''
以避免出现类型错误
>>> tpl = '''
... "unaltered": "{{foo}}",
... "replaced": "{{test}}"
... '''
>>> a = CustomTemplate(tpl)
>>> a.template
'\n "unaltered": "{{foo}}",\n "replaced": "{{test}}"\n'
>>> b = a.safe_substitute(replacement_dict)
>>> b
'\n "unaltered": "{{foo}}",\n "replaced": "hello"\n'
当我这样做时,{{foo}} 没有改变。
我尝试了上面的代码,看起来该代码实际上不适用于 python 2.7.6。我会看看是否能找到一种方法让它与 2.7.6 一起工作,因为这似乎是最近 Linux 发行版的常见版本。
update:
看起来这是 2007 年的一个已知错误。http://bugs.python.org/issue1686 http://bugs.python.org/issue1686据我所知,它于 2010 年应用于 python 3.2,并于 2014 年应用于 python 2.7。要使其发挥作用,您可以应用问题 1686 的补丁,也可以在类中使用以下命令覆盖 safe_substitute()该补丁的实际源代码https://hg.python.org/cpython/file/8a98ee6baa1e/Lib/string.py https://hg.python.org/cpython/file/8a98ee6baa1e/Lib/string.py.
此代码适用于 2.7.6 和 3.4.3
from string import Template
class CustomTemplate(Template):
delimiter = '{{'
pattern = r'''
\{\{(?:
(?P<escaped>\{\{)|
(?P<named>[_a-z][_a-z0-9]*)\}\}|
(?P<braced>[_a-z][_a-z0-9]*)\}\}|
(?P<invalid>)
)
'''
def safe_substitute(self, *args, **kws):
if len(args) > 1:
raise TypeError('Too many positional arguments')
if not args:
mapping = kws
elif kws:
mapping = _multimap(kws, args[0])
else:
mapping = args[0]
# Helper function for .sub()
def convert(mo):
named = mo.group('named') or mo.group('braced')
if named is not None:
try:
# We use this idiom instead of str() because the latter
# will fail if val is a Unicode containing non-ASCII
return '%s' % (mapping[named],)
except KeyError:
return mo.group()
if mo.group('escaped') is not None:
return self.delimiter
if mo.group('invalid') is not None:
return mo.group()
raise ValueError('Unrecognized named group in pattern',
self.pattern)
return self.pattern.sub(convert, self.template)
replacement_dict = {
"test": "hello"
}
tpl = '''{
"escaped": "{{{{",
"unaltered": "{{foo}}",
"replaced": "{{test}}",
"invalid": "{{az"
}'''
a = CustomTemplate(tpl)
b = a.safe_substitute(replacement_dict)
print (b)
results:
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import template
{
"escaped": "{{",
"unaltered": "{{foo}}",
"replaced": "hello",
"invalid": "{{az"
}
>>>