Python填充字符串,其格式为字典

时间:2017-10-25 06:44:07

标签: python dictionary format zip itertools

假设我有模板来填充dict中的值:

我有这样的模板:

templates = [
   "I have four {fruit} in {place}", 
   "I have four {fruit} and {grain} in {place}",
   ...
]

使用这样的字典:

my_dict = {'fruit': ['apple', 'banana', 'mango'], 
           'place': ['kitchen', 'living room'],
           'grain' : ['wheat', 'rice']
          }

说我有这样一句话:

sentence = "I have four apple in kitchen" 

鉴于这句话,模板和字典, 我想知道这句话匹配其中一个模板并返回它匹配的值:

{'fruit': 'apple', 'place': 'kitchen'}

与上述相似如果:

Input: "I have four apple and wheat in kitchen"
Output: {'fruit': 'apple', 'grain': 'wheat', 'place': 'kitchen'}

如果能够处理这个问题会很棒:

Input: "I have four apple in bedroom" 
Output: {'fruit': 'apple'}

注意它只返回水果,而不是卧室,因为卧室不在地方的价值观。

1 个答案:

答案 0 :(得分:6)

将格式化的字符串转换为正则表达式:

import re

words = {k: '(?P<{}>{})'.format(k, '|'.join(map(re.escape, v))) for k, v in my_dict.items()}
patterns = [re.compile(template.format(**words)) for template in templates]

这会生成I have four (?P<fruit>apple|banana|mango) in (?P<place>kitchen|living room)"形式的模式。匹配这些将为您提供预期的输出:

for pattern in patterns:
    match = pattern.match(sentence)
    if match:
        matched_words = match.groupdict()

这是一种非常快速的O(N)方法来完全匹配句子:

>>> import re
>>> templates = [
...    "I have four {fruit} in {place}",
...    "I have four {fruit} and {grain} in {place}",
... ]
>>> my_dict = {'fruit': ['apple', 'banana', 'mango'],
...            'place': ['kitchen', 'living room'],
...            'grain' : ['wheat', 'rice']
...           }
>>> def find_matches(sentence):
...     for pattern in patterns:
...         match = pattern.match(sentence)
...         if match:
...             return match.groupdict()
...
>>> find_matches("I have four apple in kitchen")
{'fruit': 'apple', 'place': 'kitchen'}
>>> find_matches("I have four apple and wheat in kitchen")
{'fruit': 'apple', 'grain': 'wheat', 'place': 'kitchen'}

如果您需要模板匹配部分句子,请将可选部分包含在(?...)组中:

"I have four {fruit} in (?{place})"

或将\w+添加到单词列表中(除了有效单词),然后在匹配后对groupdict()验证my_dict结果。对于in bedroom案例,\w+将与bedroom部分匹配,但不会在my_dict的{​​{1}}列表中找到。{ / p>