Question

我刚开始使用Python，我必须创建一个小型数据库。我使用的代码对我来说太复杂了，我遇到了一些问题。数据库的结构如下：

def load_data():
    global base
    global magazine_base
    magazine_base = shelve.open('magazine_base')
    if magazine_base.has_key('base'):
        base = magazine_base['base']
        if not base:
            base = []
    else:
        base = []
        magazine_base['base'] = base

#####Entries are made by:


base += [{
            'name': name, 
            'quantity': int(quantity),
            'price': float(price)
        }]
        magazine_base['base'] = base
        magazine_base.close()

##########And the problem is that the function to clear it all is not working properly, sometimes it doesn't remove, sometimes error, and sometimes data is cleared after restart.

def removeall():
    global magazine_base
    global base
    magazine_base.clear()
    magazine_base.items()

######For the single entry it works perfect, maybe somehow modify it to clear all the entries?

def remove():
    global base
    global magazine_base
    load_data()
    name=raw_input('Give name of a product: ')
    our_product = False
    for elem in base:
        if elem['name'] == name:
            del base[base.index(elem)]
            print 'Product deleted from the list'
            our_product = True
        if not our_product:
        print "Error! No such product in the magazine!"
    magazine_base['base'] = base
    magazine_base.close()

Answer 1

在removeall函数中，您清除magazine_base，但不清除base；根据您下一步调用的函数，可能仍会恢复base中的条目。

您可能想要做的是像在load_data中一样将其重新初始化为一个空列表：

def removeall():
    global magazine_base
    global base
    magazine_base.clear()
    base = []
    magazine_base['base'] = base

Python删除/清除数据库中的项目

1 个答案: