1. 从键盘输入两个数，并比较其大小，直到输入e/E退出程序
#encoding=utf-8
import sys
while 1:
a=input("请输入数字a:")
b=input("请输入数字b:")
if a.lower()=='e' or b.lower()=="e":
sys.exit(0)
a=float(a)
b=float(b)
if a>b:
print("%s>%s"%(a,b))
elif a<b:
print("%s<%s"%(a,b))
else:
print("%s==%s"%(a,b))
2. 将列表元素交替地作为键和值来创建字典
#encoding=utf-8
a=[1,2,3,4,5,6,7]
dic={}
for i in range(len(a)):
if len(a)%2==0:#偶数个元素
if i%2!=0:
dic[a[i-1]]=a[i]
if len(a)%2!=0:#奇数个元素
dic[a[-1]]=None
if i%2!=0:
dic[a[i-1]]=a[i]
print(dic)
3. 分别输出字符串中奇数坐标和偶数坐标的字符
#encoding=utf-8
a="abcdefgh"
odd_number_position_letters=[]
oven_number_position_letters=[]
for i in range(len(a)):
if i%2==0:
oven_number_position_letters.append(a[i])
else:
odd_number_position_letters.append(a[i])
print("奇数坐标字符:","".join(odd_number_position_letters))
print("偶数坐标字符:","".join(oven_number_position_letters))
4. 将一个字典的 key和value 互换
#encoding=utf-8
dic={1:'a',2:'b',3:'c',4:'d',5:'e'}
new_dic={}
for k,v in dic.items():
new_dic[v]=k
print(new_dic)
