python笔记4

###字典：一系列的键-值  a={'键':'值'} ，与键相关联的值：数字,字符串,列表,字典
#存储有关特定的信息
alien_0={'color':'green','points':10}
print(alien_0['color'])
print(alien_0['points'])

#访问字典中的值
alien_0={'color':'green','points':10}
a_pionts=alien_0['points']
print('YOU just earned '+str(a_pionts)+' points')
#添加键—值对
alien_0={'color':'green','points':10}
alien_0['X_position']=0
alien_0['Y_position']=5
print(alien_0)
#修改字典中的值
alien_0={'color':'green','points':10,'X_position':0,'Y_position':5}
alien_0['color']='yellow'
print(alien_0)
#根据外星人的移动速度来确定向右移动多远
alien_0={'color':'green','points':10,'X_position':1,'Y_position':5}
alien_0['speed']='medium'

if alien_0['speed']=='slow':
x_crement=1   
alien_0['x_position']=x_crement+alien_0['X_position'] #数字运算
print("The alien's new x_position is "+str(alien_0['x_position'] ))
elif alien_0['speed']=='medium':
x_crement=2
alien_0['x_position']=x_crement+alien_0['X_position']
print("The alien's new x_position is "+str(alien_0['x_position']))
else:
x_crement=3
alien_0['x_position']=x_crement+alien_0['X_position']
print("The alien's new x_position is "+str(alien_0['x_position']))
#删除键—值对
alien_0={'color':'green','points':10,'X_position':1,'Y_position':5}
del alien_0['color']
print(alien_0)
#存储多个对象的同意信息（最喜欢的语言）
favorite_languages={
    'A':"python",
    'B':'c',
    'C':'perl',
    'D':'python',
}##字典中存储多个键—值对时， 我们可以在输入左花括号后按回车，在下一行缩进四个空格,每行一个键—值对
print(favorite_languages['A'])

favorite_languages={
    'A':"python",
    'B':'c',
    'C':'perl',
    'D':'python',
}
print("C's favorite language is "+favorite_languages['C']+'.')
##遍历字典
#方法.items()
favorite_languages={
    'A':"python",
    'B':'c',
    'C':'perl',
    'D':'python',
}
for name,language in favorite_languages.items(): #for循环两个变量
print(name+"'s favorite language is "+language)

###遍历所有的键
#1
favorite_languages={
    'A':"python",
    'B':'c',
    'C':'perl',
    'D':'python',
}
for name in favorite_languages:
print(name.title())
#.keys()方法
favorite_languages={
    'A':"python",
    'B':'c',
    'C':'perl',
    'D':'python',
}
for name in favorite_languages.keys():
print(name.title())
###遍历所有的值
##.values()方法 与上面的.keys()方法相同
favorite_languages={
    'A':"python",
    'B':'c',
    'C':'perl',
    'D':'python',
}
for value in favorite_languages:
print(favorite_languages[value])
##指定的人指出其喜欢的语言(没指定的人只打印名字)
#
favorite_languages={
    'A':"python",
    'B':'c',
    'C':'perl',
    'D':'python',
}
friends=['A','C']
for name in favorite_languages:
print(name)
if name in friends:
print(name+"'s favorite language is"+favorite_languages[name])
#按顺序遍历字典中的所有键
favorite_languages={
    'A':"python",
    'D':'python',
    'B':'c',
    'C':'perl',
}
for name in sorted(favorite_languages):#sorted()函数 字母排序
print(name)
for name in sorted(favorite_languages,reverse=True): #字母反向排序
print(name)
###字典转列表
favorite_languages={
    'A':"python",
    'D':'python',
    'B':'c',
    'C':'perl',
}
print(list(favorite_languages.keys()))
print(list(favorite_languages.values()))
######嵌套（将字典存储在列表中，将列表作为值存储在字典中）
#字典列表
alien_0={'color':'green','point':5}
alien_1={'color':'yellow','point':5}
alien_2={'color':'red','point':5}
aliens=[alien_0,alien_1,alien_2]
for alien in aliens:
print(alien)
##range()生成30个外星人
aliens=[]
#创建30个绿色外星人
for alien_number in range(30): #range() 重复循环多少次
new_alien={'color':'green','point':5,'speed':'slow'}
aliens.append(new_alien)
#显示前五个外星人
for alien in aliens[:5]:
print(alien)
#打印创建了多少个外星人
print("The alien's increment is"+str(len(aliens)))
##修改外星人
aliens=[]
for alien_number in range(30):
new_alien={'color':'green','point':5,'speed':'slow'}
aliens.append(new_alien)
for alien in aliens[:3]:
if alien['color']=='green':
alien['color']='yellow'
alien['speed']='medium'
alien['point']=10
for alien in aliens[0:5]:
print(alien)
print('....')
##字典中存储列表
pizza={
    'crust':'thick',
    'toppings':['mushroom','extra cheese'],
    }
print("You odered a"+pizza['crust']+'-crust piza with the following toppings:')
for topping in pizza["toppings"]:
print(topping)
#字典中存储字典
users={
    'anny':{
        'firstname':'ann',
'lastname':"hu",
'hometown':'singapore',
},
    'curry':{
        'firstname':'li',
'lastname':"curry",
'hometown':'San Francisco',
},
    'mike':{
        'firstname':'hong',
'lastname':"mike",
'hometown':'changsha',
},
    }
for name,information in users.items():
print("User's name:"+name)
full_name=information['firstname']+' '+information['lastname']
print("Full name:"+full_name+'\nHometown:'+information['hometown']+'\n')