Python 3：如何将结果汇总到字典中

Question

我正在编写一个代码，它会查看银行对账单并根据它们所在的月份将费用/收入汇总到存储桶中。数据为 csv 格式，并以字符串条目的形式读取。 csv 文件有 5 列：第 1 列是日期，4 列是费用，5 列是收入。

代码应该：

1. 在 csv 的日期字符串中查找月份。
2. 将费用/收入添加到相应的字典中。

我在尝试将费用（格式：“$0.00”）转换为浮点数并将它们汇总到字典中时遇到了麻烦。谁能告诉我在这里我能做什么？

代码如下：

import numpy as np
import csv
import timestring as ts


months= [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
expenses = {1:0, 2:0, 3:0, 4:0, 5:0, 6:0, 7:0, 8:0, 9:0, 10:0, 11:0, 12:0}
income = {1:0, 2:0, 3:0, 4:0, 5:0, 6:0, 7:0, 8:0, 9:0, 10:0, 11:0, 12:0}
exp_cat = []
income_cat = []

files =['export.csv', 'export1.csv']

with open("budgetfile.csv","wt") as fw:
    writer = csv.writer(fw)
    for file in files:
        with open(file) as csvfile:
            records = csv.reader(csvfile, quoting=csv.QUOTE_NONE)
            print("Processing file {}. \n" .format(file))
            header = next(records)
            for row in records:
                try:
                    expenses[ts.Date(row[0]).month] += float(row[4])
                    income[ts.Date(row[0]).month] += float(row[5])
                    break
                except ValueError:
                    pass    

Answer 1

试试这个

import numpy as np
import csv
import timestring as ts
import decimal
from collections import defaultdict


months= [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
expenses = defaultdict(decimal.Decimal)
income = defaultdict(decimal.Decimal)
'''Optional for less imports
expenses = {x:decimal.Decimal() for x in months}
income = {x:decimal.Decimal() for x in months}
'''
exp_cat = []
income_cat = []

files =['export.csv', 'export1.csv']

with open("budgetfile.csv","wt") as fw:
    writer = csv.writer(fw)
    for file in files:
        with open(file) as csvfile:
            records = csv.reader(csvfile, quoting=csv.QUOTE_NONE)
            print("Processing file {}. \n" .format(file))
            header = next(records)
            for row in records:
                try:
                    expenses[ts.Date(row[0]).month] += decimal.Decimal(row[4].replace('$', ''))
                    income[ts.Date(row[0]).month] += decimal.Decimal(row[5].replace('$', ''))
                    break
                except ValueError:
                    pass