Python学习之字典

# coding=utf-8


# 字典是Python中唯一内建的映射类型，键是唯一的值不唯一，键值之间用’:'分隔，项之间用','分隔
item = [('name', 'Gumby'), ('age', 42)]
print dict(item)


# 键可以为任何不可变的类型
x = []
# 关联到列表上会有问题，应该先[None]*43对其赋值
# x[42]='Foobar'
#关联到空的字典上就不会有问题
x = {}
x[42] = 'Foobar'
print x[42]


phonebook = {'Beth': '0000', 'Alice': '1111', 'Cecil': '2222'}
print "Cecil's phone number is %(Cecil)s." % phonebook


print '字典方法'
phonebook.clear()
print phonebook


phonebook = {'Beth': '0000', 'Alice': '1111', 'Cecil': ['2222', '3333]']}
y = phonebook.copy()
print y
y['Beth'] = '888'
y['Cecil'].remove('2222')
#替换值的时候，原始字典不会修改，但如果修改的值是列表，则原始字典用户变，这是可以考虑使用deepcopy
print x
print y


print {}.fromkeys(['name','age'])
print dict.fromkeys(['name','age'], '(unknow)')


print phonebook.get('Beth')
print phonebook.has_key('Beth')
#将所有字典以列表方式返回
print phonebook.items()


#返回一个迭代器对象
it = phonebook.iteritems()
print list(it)
print phonebook.pop('Beth')
print phonebook


#随机弹出一项

print phonebook.popitem()

输出：

"D:\Program Files\Python\python.exe" G:/HelloPython/list/dict.py
{'age': 42, 'name': 'Gumby'}
Foobar
Cecil's phone number is 2222.
字典方法
{}
{'Beth': '0000', 'Alice': '1111', 'Cecil': ['2222', '3333]']}
{42: 'Foobar'}
{'Beth': '888', 'Alice': '1111', 'Cecil': ['3333]']}
{'age': None, 'name': None}
{'age': '(unknow)', 'name': '(unknow)'}
0000
True
[('Beth', '0000'), ('Alice', '1111'), ('Cecil', ['3333]'])]
[('Beth', '0000'), ('Alice', '1111'), ('Cecil', ['3333]'])]
0000
{'Alice': '1111', 'Cecil': ['3333]']}
('Alice', '1111')


Process finished with exit code 0