字典按python中的月份（按键）中的天数排序

Question

我试图按月的天数对字典进行排序。 （30,31和28）。我试图通过日历模块和日期时间模块实现这一点，但没有得到所需的输出。任何建议!!

product_sell= {'November':680,'August':678,'October':857,'January': 125,'April':989,'February': 300, 'September':120,'March':259,'December':899,'June':368, 'May':31,'July':968}

预期输出（按月数排序（键）jan，march ... = 31，feb = 28，4月，6月.. = 30）

product_sell= {'January': 125, 'March':259, 'May':31, 'July':968, 'August':678,  'October':857, 'December':899, 'April':989, 'June':368, 'September':120, 'November':680, 'February': 300}

Answer 1

你不能对字典进行排序，因为它是无序的。您可以使用ordereddict来实现此目的。

from collections import OrderedDict

product_sell= {'November':680,'August':678,'October':857,'January': 125,'April':989,'February': 300, 'September':120,'March':259,'December':899,'June':368, 'May':31,'July':968}
months = ['January','February','March','April','May','June','July','August','September','October','November','December']

OrderedDict(sorted(product_sell.items(),key =lambda x:months.index(x[0])))

输出：

OrderedDict([('January', 125),
         ('February', 300),
         ('March', 259),
         ('April', 989),
         ('May', 31),
         ('June', 368),
         ('July', 968),
         ('August', 678),
         ('September', 120),
         ('October', 857),
         ('November', 680),
         ('December', 899)])

Answer 2

如果您只想使用（打印，写入文件，......）数据，则无需创建新的（有序）字典。只需输出(month, count)项目列表。

>>> product_sell= {'November':680,'August':678,'October':857,'January': 125,'April':989,'February': 300, 'September':120,'March':259,'December':899,'June':368, 'May':31,'July':968}    

首先，您可以按月构建排序键：

>>> import calendar
>>> key_by_month = dict(zip(calendar.month_name[1:], [(-calendar.monthrange(2019,i)[1], i) for i in range(1,13)]))
>>> key_by_month
{'January': (-31, 1), 'February': (-28, 2), 'March': (-31, 3), 'April': (-30, 4), 'May': (-31, 5), 'June': (-30, 6), 'July': (-31, 7), 'August': (-31, 8), 'September': (-30, 9), 'October': (-31, 10), 'November': (-30, 11), 'December': (-31, 12)}

月份将按天数（降序，因此减号）排序，然后按其自然顺序排序。

其次，使用sorted并按月名找到密钥：

>>> sorted(product_sell.items(), key=lambda m_c: key_by_month[m_c[0]])
[('January', 125), ('March', 259), ('May', 31), ('July', 968), ('August', 678), ('October', 857), ('December', 899), ('April', 989), ('June', 368), ('September', 120), ('November', 680), ('February', 300)]

注意：如果可以，请避免使用月份名称作为键，因为它们可能会有变化：“january”vs“January”，外语，......