python day5

列表:
#
l=[1,2,3] #l=list([1,2,3]) # print(type(l)) #优先掌握 #  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)

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['name'])
# 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','sex':'male','age':18,}
# # info_dic.pop()
# info_dic.popitem()
# print(info_dic)
# del info_dic['name']
# print(info_dic)

#
#     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)
#

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('===>')
原文地址:https://www.cnblogs.com/jmblog/p/7212273.html