使用字符串实现如下练习

 

nums = '112233'
lst = [None] * 10

for i in range(10):
    lst[i] = nums.count(str(i))
    if lst[i]:
        print(i,lst[i])
print('---------------')


nums = '112233'
lst = [None] * 10
for x in nums:
    i = int(x)
    if lst[i] == None:
        lst[i] = nums.count(x)
        print(i,lst[i])


print('---------------')
nums = '1122330'
lst = [0] * 10

for x in nums:
    i = int(x)
    lst[i] +=1
print(lst)
for i in range(len(lst)):
    if lst[i]:
        print(i,lst[i])

 

num = []
while len(num) < 5:
    num = input('please input a number: ').strip().lstrip('0')
    if not num.isdigit():
        break
    print('the number {} length is {}'.format(num,len(num)))

nums = list(num)
for i in range(len(nums)-1):
    flag = False
    for j in range(len(nums)-i-1):
        if nums[j] > nums[j + 1]:
            nums[j],nums[j+1] = nums[j+1],nums[j]
            flag = True
    if not flag:
        break
print(nums)