循环，元组，字典，列表，代码整理

Posted 2020-09-29 不会起名字

循环

# msg=‘hello‘
# msg=[1,2,3,4,5,6]
msg=(1,2,3,4,5,6)
msg_dic={
‘apple‘:10,
‘tesla‘:1000000,
‘mac‘:3000,
‘lenovo‘:30000,
‘chicken‘:10,
}
index=0
while index < len(msg):
    print(msg[index])
    index+=1

msg=‘hello‘
# msg=[‘a‘,‘b‘,‘c‘,‘d‘,‘e‘]
# msg=(‘a‘,‘b‘,‘c‘,‘d‘,‘e‘)
for i in range(len(msg)):
    print(i,msg[i])

不依赖索引的取值
for item in msg_dic:
    print(item,msg_dic[item])
msg=‘hello‘
msg=[1,2,3,4,5,6]
msg=(1,2,3,4,5,6)
for item in msg:
    print(item)
补充
range:顾头不顾尾，默认从0开始
print(type(range(1,2)))
for i in range(10):
    print(i,type(i))
for i in range(1,10,2):
    print(i,type(i))
for i in range(10,1,-2):
    print(i)
for i in range(1,10,1):
    print(i)
for i in range(9,0,-1):
    print(i)
break
continue
for i in range(10):
    if i == 4:
        # break
        continue
    print(i)
for+else
for i in range(10):
    print(i)
    break
else:
    print(‘===>‘)

元组

为何要有元组，存放多个值，元组不可变，更多的是用来做查询
t=(1,[1,3],‘sss‘,(1,2)) #t=tuple((1,[1,3],‘sss‘,(1,2)))
print(type(t))

#元组可以作为字典的key
d={(1,2,3):‘egon‘}
print(d,type(d),d[(1,2,3)])
　索引
　　　　切片
goods=(‘iphone‘,‘lenovo‘,‘sanxing‘,‘suoyi‘)
print(goods[1:3])

　　　　长度

in:
字符串:子字符串
列表：元素
元组：元素
字典：key

goods=(‘iphone‘,‘lenovo‘,‘sanxing‘,‘suoyi‘)
print(‘iphone‘ in goods)

d={‘a‘:1,‘b‘:2,‘c‘:3}
print(‘b‘ in d)

掌握
goods=(‘iphone‘,‘lenovo‘,‘sanxing‘,‘suoyi‘)
print(goods.index(‘iphone‘))
print(goods.count(‘iphone‘))

补充：元组本身是不可变的，但是内部的元素可以是可变类型
t=(1,[‘a‘,‘b‘],‘sss‘,(1,2)) #t=tuple((1,[1,3],‘sss‘,(1,2)))

t[1][0]=‘A‘
print(t)
t[1]=‘aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa‘

字典

info=[‘egon‘,‘male‘,18,180,75]

info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
常用操作：

　　　　存/取
info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
print(info_dic[‘name11111111‘])
print(info_dic.get(‘name‘,None))

pop：key存在则弹出值，不存在则返回默认值，如果没有默认值则报错
print(info_dic.pop(‘nam123123123123123123e‘,None))
print(info_dic)

print(info_dic.popitem())
print(info_dic)

info_dic[‘level‘]=10
print(info_dic)
　　　　删除
info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
info_dic.pop()
info_dic.popitem()

del info_dic[‘name‘]

　　　　键s，值s，键值对
info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
print(info_dic.keys())
print(info_dic.values())
print(info_dic.items())

for k in info_dic:
    # print(k,info_dic[k])
    print(k)
print(‘========>‘)
for k in info_dic.keys():
    print(k)
for val in info_dic.values():
    print(val)
for k,v in info_dic.items(): #k,v=(‘name‘, ‘egon‘)
    print(k,v)

　　　　长度
info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
print(len(info_dic))

　　　　循环
#
　　　　包含in

info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
print(‘name‘ in info_dic)
print(‘name‘ in info_dic.keys())
print(‘egon‘ in info_dic.values())
print((‘name‘,‘egon‘) in info_dic.items())

掌握
info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
info_dic.update({‘a‘:1,‘name‘:‘Egon‘})
print(info_dic)

info_dic[‘hobbies‘]=[]
info_dic[‘hobbies‘].append(‘study‘)
info_dic[‘hobbies‘].append(‘read‘)
print(info_dic)

setdefault:key不存在则设置默认值，并且放回值默认值
key存在则不设置默认，并且返回已经有的值

info_dic.setdefault(‘hobbies‘,[1,2])
print(info_dic)
info_dic.setdefault(‘hobbies‘,[1,2,3,4,5])
print(info_dic)

info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}

{‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘,‘hobbies‘:[‘study‘]}
info_dic.setdefault(‘hobbies‘,[]).append(‘study‘)

{‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘,‘hobbies‘:[‘study‘,‘read‘]}
info_dic.setdefault(‘hobbies‘,[]).append(‘read‘)

{‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘,‘hobbies‘:[‘study‘,‘read‘,‘sleep‘]}
info_dic.setdefault(‘hobbies‘,[]).append(‘sleep‘)
l=info_dic.setdefault(‘hobbies‘,[])
print(l,id(l))
print(id(info_dic[‘hobbies‘]))

print(info_dic)

了解
d=info_dic.copy()
print(d)
info_dic.clear()
print(info_dic)

d=info_dic.fromkeys((‘name‘,‘age‘,‘sex‘),None)
print(d)
d1=dict.fromkeys((‘name‘,‘age‘,‘sex‘),None)
d2=dict.fromkeys((‘name‘,‘age‘,‘sex‘),(‘egon‘,18,‘male‘))
print(d1)
print(d2)

info=dict(name=‘egon‘,age=18,sex=‘male‘)
print(info)

info=dict([(‘name‘,‘egon‘),(‘age‘,18)])
print(info)

列表

l=[1,2,3] #l=list([1,2,3])
print(type(l))

pat1===》优先掌握部分
　索引
　　　　切片
l=[‘a‘,‘b‘,‘c‘,‘d‘,‘e‘,‘f‘]

print(l[1:5])
print(l[1:5:2])
print(l[2:5])
print(l[-1])

了解
print(l[-1:-4])
print(l[-4:])
l=[‘a‘,‘b‘,‘c‘,‘d‘,‘e‘,‘f‘]
print(l[-2:])

　　　　追加
hobbies=[‘play‘,‘eat‘,‘sleep‘,‘study‘]
hobbies.append(‘girls‘)
print(hobbies)

　　　　删除
hobbies=[‘play‘,‘eat‘,‘sleep‘,‘study‘]
x=hobbies.pop(1) #不是单纯的删除，是删除并且把删除的元素返回，我们可以用一个变量名去接收该返回值
print(x)
print(hobbies)

x=hobbies.pop(0)
print(x)

x=hobbies.pop(0)
print(x)

队列：先进先出
queue_l=[]
#入队
queue_l.append(‘first‘)
queue_l.append(‘second‘)
queue_l.append(‘third‘)
print(queue_l)
出队
print(queue_l.pop(0))
print(queue_l.pop(0))
print(queue_l.pop(0))

堆栈:先进后出，后进先出
l=[]
#入栈
l.append(‘first‘)
l.append(‘second‘)
l.append(‘third‘)
#出栈
print(l)
print(l.pop())
print(l.pop())
print(l.pop())

了解
del hobbies[1] #单纯的删除
hobbies.remove(‘eat‘) #单纯的删除，并且是指定元素去删除
　　　　长度
hobbies=[‘play‘,‘eat‘,‘sleep‘,‘study‘]
print(len(hobbies))

　　　　包含in
hobbies=[‘play‘,‘eat‘,‘sleep‘,‘study‘]
print(‘sleep‘ in hobbies)

msg=‘hello world egon‘
print(‘egon‘ in msg)

#pat2===》掌握部分
hobbies=[‘play‘,‘eat‘,‘sleep‘,‘study‘,‘eat‘,‘eat‘]
hobbies.insert(1,‘walk‘)
hobbies.insert(1,[‘walk1‘,‘walk2‘,‘walk3‘])
print(hobbies)

print(hobbies.count(‘eat‘))
print(hobbies)
hobbies.extend([‘walk1‘,‘walk2‘,‘walk3‘])
print(hobbies)

hobbies=[‘play‘,‘eat‘,‘sleep‘,‘study‘,‘eat‘,‘eat‘]
print(hobbies.index(‘eat‘))

pat3===》了解部分
hobbies=[‘play‘,‘eat‘,‘sleep‘,‘study‘,‘eat‘,‘eat‘]
hobbies.clear()
print(hobbies)

l=hobbies.copy()
print(l)

l=[1,2,3,4,5]
l.reverse()
print(l)

l=[100,9,-2,11,32]
l.sort(reverse=True)
print(l)