第二周作业

习题3-4,3-5,3-6,3-7
打印嘉宾名单并使用insert,pop,append函数多次修改该名单
guest_list=['john','mike','duke','firefly']
print(guest_list)
print (guest_list[1]+' can not arrive the party!')
guest_list[1]='king'
for sub in guest_list:
print('welcome! '+sub)
print('bigger table found!')
guest_list.insert(0,'first')
guest_list.append('last')
num=len(guest_list)/2
guest_list.insert(int(num), 'mid')
print (guest_list)
for sub in guest_list:
print('welcome! '+sub)

print("\nsorry, some error occur, only 2 guests are needed\n")
count=len(guest_list)
while count>2:
sub=guest_list.pop()
count-=1
print('sorry '+sub)
for sub in guest_list:
print(sub+'you are still in the list!')
del guest_list[0]
del guest_list[-1]
print (guest_list)注意到insert的参数是个int值，使用之前应该用int（）函数将其他数据类型转化为int，len（）可以求出列表的长度
4-13
food=('a','b','c','d','e')
for target in food:
print(target)
food[1]='asdfsadf'
food=('a1','b','c1','d','e')
for sub in food:
print (sub)
4-3到4-9
nums=list (range(1,20))
for sub in nums:
print(sub)
nums=list(range(1,10000))
for sub in nums:
print (sub)
print(str(sum(nums))+'\n')
nums=list(range(3,20,3))
for sub in nums:
print(sub)
print('\n')
nums.clear()
for i in range(3,30):
if i%3==0:
nums.insert(-1,i)
#print('i:'+str(i))
#i+=1
print (nums)
nums=[a**3 for a in range(1,10)]
print(nums)