Python字典按日期分组键答案

【问题标题】：Python Dict Grouping by Date on KeyPython字典按日期分组键
【发布时间】：2020-04-16 18:25:26
【问题描述】：

我有一个字典，它的键是日期，它的项目是一些数字和带有Total 的数字的总和，如下所示。我想用它们的 Total 值的总和按年份对键进行分组。如果我使用固定的字典，我知道该怎么做。但我总是会写出不同的可变日期。我的示例列表是；

{
        "15-12-2017" : {
          "1" : "abc",
          "2" : "def",
          "Total" : "2"
        },
        "16-12-2017" : {
          "1" : "ghi",
          "2" : "jkl",
          "3" : "mno",
          "Total" : "3"
        }
        "17-12-2017" : {
          "1" : "ghi",
          "2" : "jkl",
          "3" : "mno",
          "4" : "pqr",
          "Total" : "4"
        }
        "15-12-2018" : {
          "1" : "ghi",
          "2" : "jkl",
          "3" : "mno",
          "Total" : "3"
        }
        "16-12-2018" : {
          "1" : "ghi",
          "2" : "jkl",
          "Total" : "2"
        }
        "18-12-2019" : {
          "1" : "ghi",
          "2" : "jkl",
          "3" : "mno",
          "Total" : "3"
        }
}

我想获得一个新的列表，例如；

{"2017":9,"2018":5,"2019":3}

我只能这样做；

for key in my_list:
    if key.split('-')[2] == '2017':
        l_2017.append(key)

但正如我之前所说，我将插入许多可变日期。我怎样才能像这种格式那样对它们进行聚类？

【问题讨论】：

标签： python-3.x date datetime dictionary grouping

【解决方案1】：

这是一种方法：

from dateutil.parser import parse

date_data = {
    "15-12-2017" : {
        "1" : "abc",
        "2" : "def",
        "Total" : "2"
    },
    "16-12-2017" : {
        "1" : "ghi",
        "2" : "jkl",
        "3" : "mno",
        "Total" : "3"
    },
    "17-12-2017" : {
        "1" : "ghi",
        "2" : "jkl",
        "3" : "mno",
        "4" : "pqr",
        "Total" : "4"
    },
    "15-12-2018" : {
        "1" : "ghi",
        "2" : "jkl",
        "3" : "mno",
        "Total" : "3"
    },
    "16-12-2018" : {
        "1" : "ghi",
        "2" : "jkl",
        "Total" : "2"
    },
    "18-12-2019" : {
        "1" : "ghi",
        "2" : "jkl",
        "3" : "mno",
        "Total" : "3"
    }
}

sums = {}

for date, data in date_data.items():
    year = str(parse(date).year)
    total = int(data['Total'])
    # Update sum if already tracking, otherwise create new entry in dictionary
    sums[year] = sums[year] + total if year in sums else total

print(sums)

这给出了输出：

{'2017': 9, '2018': 5, '2019': 3}

【讨论】：