python – 我们如何修改搁置中的数据？

2019年8月4日 181次阅读

我使用以下代码打开了一个货架：

#!/usr/bin/python
import shelve                   #Module:Shelve is imported to achieve persistence

Accounts = 0
Victor = {'Name':'Victor Hughes','Email':'victor@yahoo.com','Deposit':65000,'Accno':'SA456178','Acctype':'Savings'}
Beverly = {'Name':'Beverly Dsilva','Email':'bevd@hotmail.com','Deposit':23000,'Accno':'CA432178','Acctype':'Current'}

def open_shelf(name='shelfile.shl'):
    global Accounts
    Accounts = shelve.open(name)          #Accounts = {}
    Accounts['Beverly']= Beverly    
    Accounts['Victor']= Victor


def close_shelf():
    Accounts.close()

我能够将值附加到货架但无法修改值.
我已经定义了一个函数Deposit(),我想从中修改shelve中存在的数据.但是它给了我以下错误：

Traceback (most recent call last):
  File "./functest.py", line 16, in <module>
    Deposit()
  File "/home/pavitar/Software-Development/Python/Banking/Snippets/Depositfunc.py", line 18, in Deposit
    for key in Accounts:
TypeError: 'int' object is not iterable

这是我的功能：

#!/usr/bin/python

import os                       #This module is imported so as to use clear function in the while-loop
from DB import *                       #Imports the data from database DB.py

def Deposit():
        while True:
                os.system("clear")              #Clears the screen once the loop is re-invoked
                input = raw_input('\nEnter the A/c type: ')
                flag=0
                for key in Accounts:
                        if Accounts[key]['Acctype'].find(input) != -1:
                                amt = input('\nAmount of Deposit: ')
                                flag+=1
                                Accounts[key]['Deposit'] += amt

                if flag == 0:
                        print "NO such Account!"    

if __name__ == '__main__':
        open_shelf()
        Deposit()
        close_shelf()

我是Python的新手.请帮忙.如果我错了,请更正我.我需要有人对这段代码的功能给出一些解释.我很困惑.

最佳答案 首先,不要使用全局帐户,而是来回传递它.使用全局导致您的错误.像这样：

def open_shelf(name='shelfile.shl'):
    Accounts = shelve.open(name)          #Accounts = {}
    ...
    return Accounts

def close_shelf(Accounts):
    Accounts.close()


def Deposit(Accounts):
    ...   

if __name__ == '__main__':
    Accounts = open_shelf()
    Deposit(Accounts)
    close_shelf(Accounts)

其次,不要重新定义内置函数.在Deposit()中,将raw_input的结果分配给名为input的变量：

input = raw_input('\nEnter the A/c type: ')

四行之后,您尝试使用内置输入功能：

amt = input('\nAmount of Deposit: ')

但这不起作用,因为输入已被重新定义！

第三,当迭代搁置物品时,遵循以下模式：1)抓住搁置物品,2)变异物品,3)将变异物品写回架子.像这样：

for key, acct in Accounts.iteritems():  # grab a shelved item
    if val['Acctype'].find(input) != -1:
        amt = input('\nAmount of Deposit: ')
        flag+=1
        acct['Deposit'] += amt          # mutate the item
        Accounts[key] = acct            # write item back to shelf

(第三点建议是从hughdbrown的答案中调整过的.)

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