使用字典

#一个简单的字典
alien_0 = {'color': 'green', 'points': 5}#访问字典中的值
print(alien_0['color'])#添加键值对
alien_0['x_position'] = 4
alien_0['y_position'] = 33
print(alien_0)#修改字典中的值
alien_0['color'] = 'red'
print(alien_0)#删除键值对
del alien_0['points']
print(alien_0)#使用get()来访问
point_value = alien_0.get('points')
print(point_value) #None
point_value = alien_0.get('points', "No point value assigned.")
print(point_value) #No point value assigned.

遍历字典

#遍历键值对
user_0 = {'username': 'efermi','first': 'enrico','last': 'fermi'
}
for key, value in user_0.items():print(f"key={key}, value={value}")#遍历keys
favorite_languages = {'jen': 'python','sarah': 'c','edward': 'ruby','phil': 'python'
}
for name in favorite_languages.keys():print(name.title())#按特定顺序遍历keys
favorite_languages = {'jen': 'python','sarah': 'c','edward': 'ruby','phil': 'python'
}
for name in sorted(favorite_languages.keys()):print(name.title())#遍历values
favorite_languages = {'jen': 'python','sarah': 'c','edward': 'ruby','phil': 'python'
}
for lanage in favorite_languages.values():print(lanage.title())

嵌套