使用正则表达式根据值列表对字典列表进行排序

Question

我想根据 list_months 对 list_of_dicts 的键进行排序。一旦我从 list_of_dicts 的键中删除数字（年），它就可以正常工作，但我无法弄清楚如何在 lambda 函数中正确使用正则表达式来包含数字。

到目前为止我的代码：

import re
list_months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
list_of_dicts = [{'Apr23': '64.401'}, {'Aug23': '56.955'}, {'Dec23': '57.453'}, {'Feb23': '90.459'}, {'Jan23': '92.731'}, {'Jul23': '56.6'}, {'Jun23': '56.509'},{'Mar23': '86.209'}, {'May23': '58.705'}, {'Nov23': '57.368'}, {'Oct23': '56.711'}, {'Sep23': '57.952'}]

r = re.compile("[a-zA-Z]{3}[0-9]{2}")
    
print(sorted(list_of_dicts, key=lambda d: [k in d for k in list_months if re.search(r, k)], reverse=True))

Answer 1

这里不需要正则表达式。

dict_months = {m:i for i, m in enumerate(list_months)}
result = sorted(list_of_dicts, key=lambda d: dict_months[next(iter(d))[:3]])
print(result)
# [{'Jan23': '92.731'}, {'Feb23': '90.459'}, {'Mar23': '86.209'}, {'Apr23': '64.401'}, {'May23': '58.705'}, {'Jun23': '56.509'}, {'Jul23': '56.6'}, {'Aug23': '56.955'}, {'Sep23': '57.952'}, {'Oct23': '56.711'}, {'Nov23': '57.368'}, {'Dec23': '57.453'}]

如果您还想考虑年份，请使用

def sortby(d):
    key = next(iter(d))
    return int(key[3:]), dict_months[key[:3]]

result = sorted(list_of_dicts, key=sortby)

Answer 2

使用 re.sub 和 list.index 的一种方法。

注意 list.index 是 O(n)，这是相当昂贵的。

def get_key_loc(dic):
    k = list(dic.keys())[0]
    return list_months.index(re.sub("\d+", "", k))

sorted(list_of_dicts, key=get_key_loc)

输出：

[{'Jan23': '92.731'},
 {'Feb23': '90.459'},
 {'Mar23': '86.209'},
 {'Apr23': '64.401'},
 {'May23': '58.705'},
 {'Jun23': '56.509'},
 {'Jul23': '56.6'},
 {'Aug23': '56.955'},
 {'Sep23': '57.952'},
 {'Oct23': '56.711'},
 {'Nov23': '57.368'},
 {'Dec23': '57.453'}]

Answer 3

你真的不需要 dict_month，使用 python 的 batteries included:

from datetime import datetime

sorted(list_of_dicts, key=lambda x: datetime.strptime(next(iter(x)), '%b%d'))

或：

import dateutil.parser

sorted(list_of_dicts, key=lambda x: dateutil.parser.parse(next(iter(x))))

输出：

[{'Jan23': '92.731'},
 {'Feb23': '90.459'},
 {'Mar23': '86.209'},
 {'Apr23': '64.401'},
 {'May23': '58.705'},
 {'Jun23': '56.509'},
 {'Jul23': '56.6'},
 {'Aug23': '56.955'},
 {'Sep23': '57.952'},
 {'Oct23': '56.711'},
 {'Nov23': '57.368'},
 {'Dec23': '57.453'}]

使用正则表达式根据值列表对字典列表进行排序

Sort a list of dicts according to a list of values with regex

python

lambda

dictionary

list-comprehension

list