用于eval的python字符串转换

当然你必须是 very careful 使用eval。我很想知道你为什么要用eval来做这个

import re
exp = 'qty * price - discount + 100'
exp = re.sub('(qty|price|discount)','%(\\1)f', exp)%vars(obj)

我假设您拥有的列表是可用obj属性的列表。

如果是这样,我建议使用正则表达式,如下所示:

import re

properties = ['name', 'country_id', 'price', 'rate', 'discount', 'qty']
prefix = 'obj'
exp = 'qty * price - discount + 100'

r = re.compile('(' + '|'.join(properties) + ')')
new_exp = r.sub(prefix + r'.\1', exp)

keys = ['name','country_id', 'price','rate','discount', 'qty']
exp = 'qty * price - discount + 100'

for key in keys:
    exp = exp.replace(key, '%s.%s' % ('your_object', key))

输出:

'your_object.qty * your_object.price - your_object.discount + 100'