python基础：元组；字典·；迭代查询·

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概述

# a=input('请输入字符串：')
# b=0
# i=0
# while i<len(a):
#
if '0'<=a[i]<='9':
#
b=b*10+int(a[i])
#
i+=1
# print(b)

‘’‘元组’’’

# a=(1,2,3,4,5,6,7)
# print(type(a))
#type：tuple元组
# for i in a:
#
print(i)

# i=0
# while i<len(a):
#
print('第{}个数是{}'.format(i+1,a[i]))
#
i+=1

print(a[6:0:-1]
#6是下标对应的最后一个，0对应第一个但是是开区间取不到下标为0的，-1是倒序
print(a[-1:-3:-1])

# b=(1)
# print(type(b))
# b=(1,)
#元组中只有一个元素是必须在后面加 ， 才是元组，否则是整数
# print(type(b))
# b=()

# print(type(b))
#tyoe:元组
# a,b=(1,2,3)
#报错
# a,b=(1,)
#报错
# a,b="xy"
# print(a)
# print(b)

# a=(1,2,3)
# b=[4,5,6]
# i=0
# for ys in a:
#
b.insert(i,ys)
#
i+=2
# print(b)
# b.extend(a)
#只有列表可以更改
# a.extend(b)
#元组不可更改
# print(a)
# print(b)

# a=[[1,2,3],[4,5],[6,7,8],['a','b','c']]
'''while-while'''
# i=0
# while i<len(a):
#
j=0
#
while j<len(a[i]):
#
print(a[i][j],end=' ')
#
j+=1
#
print()
#
i+=1
'''while-for'''
# i=0
# while i<len(a):
#
for j in a[i]:
#
print(j,end=' ')
#
print()
#
i+=1
# print(a[i],type(a[i]))
'''for-while'''
# for i in a:
#
j=0
#
while j<len(i):
#
print(i[j],end=' ')
#
j+=1
#
print()
'''for-for'''
# for i in a:
# i 是元素
#
for j in i:
#
print(j,end=' ')
#
print()
# for i in range(0,len(a),1):
# range里i 是下标
#
for j in range(0,len(a[i]),1):
#
print(a[i][j],end=' ')
#
print()

‘’‘字典’’’

# a={'name':'小红','age':18,'sex':'女','address':'辽宁'}
# print(a['name'])
# print(a.keys())
# a['name']='小明'
#修改
# print(a)
# a['age']=99
# print(a)
# a['sex']='男'
# print(a)
# del a['name']
# print(a)
# a.pop('sex')
# print(a)

# b=dict(name='李雷',age=20,address='教科书')
# print(b)
# print(b[sex])

# print(b.get('name'))
# print(b.get('sex','男'))
# get 没有的，输出的是后边的值
# print(b)
# print(b.get('name','小红'))
#get 的是存在的，输出的是原值

# print(b.keys())
#输出 键
# for key in b.keys():
#
print(key,b[key])
#输出 值
# print(b.values())

# for v in b.values():
#
print(v)

# a={'name':'韩梅梅','age':'14','sex':'女'}
# for k,v in a.items():
#
print(k,v)
#
# a.pop('name')
# print(a.pop('name'))
# print(a)
# print(a)
# a.pop('name')
# print(a)
# print(a.popitem())
#打印出 删除的最后一个
# print(a)

# a='123'*9
# print(a)
# b='我是'+'小可爱'
# print(b)

# a={
#
'001':{'name':'张三','age':19,'address':'北京'},
#
'002':{'name':'李四','age':18,'address':'上海'},
#
'003':{'name':'王五','age':20,'address':'广州'},
#
'004':{'name':'小红','age':24,'address':'北京'},
#
'005':{'name':'李明','age':22,'address':'广州'}
# }
# for i,j in a.items():
#
if j['address']=='北京':
#
j['house']=10000
#print(i,a[i])
# for k in a.keys():
#迭代查询 a 的键
#
if a[k]['address']=='北京':
#a[k]是k对应的值 值是字典，那么用字典[address]或地址的值 如：北京
#
a[k]['house']=10000
#在值的字典里增加[house]项
# for i,j in a.items():
#
print(i,j)

# for i in a.keys():
# 把 a 里面的值一个个拿出来给 i
#
print(i,end=' ')
#
for k in a[i].keys():
#a[i]是i 对应的value，也是一个字典，字典有keys属性
#
print(k,a[i][k],end=' ')
#
for k,v in a[i].items():
#
print(k,v,end=' ')
#
print()