字典

%字典用keys来连接values
1 x = {'Christopher Brooks': 'brooksch@umich.edu', 'Bill Gates': 'billg@microsoft.com'}
2 x['Christopher Brooks'] # Retrieve a value by using the indexing operator

'brooksch@umich.edu'

1 x['Kevyn Collins-Thompson'] = None
2 x['Kevyn Collins-Thompson']

None

%迭代遍历所有的keys
1 for name in x:
2     print(x[name])

brooksch@umich.edu
billg@microsoft.com
None

%迭代遍历所有的值
1 for email in x.values():
2     print(email)

brooksch@umich.edu
billg@microsoft.com
None

%迭代在列表中的所有项
1 for email, name in x.items():
2     print(name)
3     print(email)

brooksch@umich.edu
Christopher Brooks
billg@microsoft.com
Bill Gates
None
Kevyn Collins-Thompson