四年级音乐教学计划,深圳房产网,丹东中考成绩查询
eg1:
user_0 = {
'username': 'efermi',
'first': 'enrico',
'last': 'fermi',
}
for key, value in user_0.items():
print("\nkey: " + key)
print("value: " + value)
for key, value in user_0.items(): 也可简化为 for k, v in user_0.items(): 但对于这两个变量是可以使用任何名称,并不局限于此。
eg2: 打印出每个人喜欢的语言
favorite_languages = {
'jen': 'python',
'sarah': 'c',
'edward': 'ruby',
'phil': 'python',
}
for name, language in favorite_languages.items():
print(name.title() + "'s favorite language is " + language.title() + ".")
for name in favorite_languages.keys():
print(name.title())
或省略keys(),输出不变for name in favorite_languages:
print(name.title())
找出两位朋友喜欢的语言:
friends = ['phil', 'sarah']
for name in favorite_languages.keys():
if name in friends:
print("hi " + name.title() + ", i see your favorite language is " + favorite_languages[name].title() + "!")
确定某个人是否接受了调查
if 'eric' not in favorite_languages.keys():
print("erin, please take our poll!")
for name in sorted(favorite_languages.keys()):
print(name.title() + ", thank you for taking the poll.")
调用sorted( )函数让字典中所有键在遍历前排序。
print('the following languages have been mentioned:')
for language in favorite_languages.values():
print(language.title())
运行结果:
the following languages have been mentioned:
python
c
ruby
python
打印出了字典中的所有值,但字典中的值是可以重复的,结果也就出现了重复,为此可以使用集合set( )提出重复:
print('the following languages have been mentioned:')
for language in set(favorite_languages.values()):
print(language.title())
运行结果:
the following languages have been mentioned:
python
ruby
c
note: 遍历字典时,键值的返回顺序是不定的,键和值的对应是固定。
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