姓名格式处理，"Last Name, First Name"

        输入格式：Last Name, First name
        如果输入的格式： First name LastName(没有逗号)
        互换位置，提示错误，记录错误数
        输入完毕后，排序输出

        这里以q退出，done输入完毕

all = []
count = 0
error = 1
while True:
    name = input("Please enter name %d :" % count)
    if len(name.split(',')) == 2:
        all.append(name)
        count += 1
    elif name == 'q': break
    elif name == 'done':
        print("The sorted list (by last name) is:")
        for i in sorted(all):
            print('   ',i)
        break
    elif len(name.split(' ')) == 2:
        tmp = name.split(' ')
        name = tmp[1].strip() + ', ' + tmp[0].strip()
        all.append(name)
        print("Wrong format... should be Last, First.")
        print("You have done this %d time(s) already.Fixing input..." % error)
        error += 1
        count += 1
    else:
        print("enter error, try agent.")
        continue

---

Please enter name 0 :Smith, Joe

Please enter name 1 :Mary Wong

Wrong format... should be Last, First.

You have done this 1 time(s) already.Fixing input...

Please enter name 2 :Hamilton, Gerald

Please enter name 3 :done

The sorted list (by last name) is:

    Hamilton, Gerald

    Smith, Joe

    Wong, Mary