遍历字典

Python支持对字典的遍历，有多种遍历字典的方式：所有的键值对，键或者值。

遍历所有的键值对：

people = {'name':'winter',
          'age':'25',
 'sex':'man',
 }
for key,value in people.items():
print("\nkey:"+key)
print("value:"+value)

key:name
value:winter

key:age
value:25

key:sex
value:man

favourite_language={'winter':'python',
                    'thunder':'shell',
 'amy':'C'}
for name,language in favourite_language.items():
print(name.title()+"`s favourite language is "+language.title()+ ' .')

Winter`s favourite language is Python .
Thunder`s favourite language is Shell .
Amy`s favourite language is C .

遍历所有的键：

favourite_language={'winter':'python',
                    'thunder':'shell',
 'amy':'C'}
for name in favourite_language.keys(): #遍历字典时默认遍历所有的键，因此key（）方法加不加都可以，加上之后更容易理解。
print(name)

winter
thunder
amy
按照顺序遍历所有键：

favourite_language={'winter':'python',
                    'thunder':'shell',
 'amy':'C'}
for name in sorted(favourite_language.keys()): #利用sorted()函数对字典的键进行一个排序。
print(name)

amy
thunder
winter

遍历所有的值：

favourite_language={'winter':'python',
                    'thunder':'shell',
 'amy':'C',
 'dongtian':'python'}
for language in favourite_language.values(): #使用方法values()可以遍历字典所有的值。
print(language)
python
shell
C
python
这种做法提取字典中所有的值，但是没有考虑是否有重复的。

favourite_language={'winter':'python',
                    'thunder':'shell',
                    'amy':'C',
                    'dongtian':'python'}
for language in set(favourite_language.values()):   #使用方法values()可以遍历字典所有的值,使用set()函数可以使值为唯一的
    print(language)

shell
python
C