排序,其他的运用 os fork

 while True:
     str_num = input("Enter number:")

     flag = True
     dotCount = 0
     if str_num[0] == '-':
         str_num_copy = str_num[1:]
     else:
         str_num_copy = str_num
     for ch in str_num_copy:
         if ch>='' and ch <= '':
             continue
         elif ch == '.':
             dotCount += 1
             if dotCount>1:
                 flag = False
                 print("您输入的内容不规范,请重新输入")
                 break
             continue
         else:
             flag = False
             print("您输入的内容不规范,请重新输入")
             break
     if flag == True:
         print(float(str_num))
         break

 # import math
 # while True:
 #     x = input('Enter number:')
 #     y = int(x) / 6
 #     num = math.ceil(y)
 #     print(num)
 # # 用列表解析的方式
 # while True:
 #     x = input('Enter number:')
 #     num = int(x)
 #     page = num // 6
 #     n = 1 if num%6!=0 else 0
 #     print(page+n)

 #排序
 # list1 = [5,4,3,2,1,2,3,4,5]
 # #对list1进行排序 排序之后改变了id号
 # l = sorted(list1)#result:[1, 2, 2, 3, 3, 4, 4, 5, 5]
 # print(l)#[1, 2, 2, 3, 3, 4, 4, 5, 5]
 # print(id(l),id(list1))#43557960 43558536
 #
 # list1 = [5,4,3,2,1,2,3,4,5]
 # #对list1进行排序 排序之后改变了id号
 # l = list1.sort()
 # print(l,list1)# None [1, 2, 2, 3, 3, 4, 4, 5, 5]
 # print(id(l),id(list1))#1790284944 43688648
 #
 # list1 = [5,4,3,2,1,2,3,4,5]
 # print(id(list1))#43689032
 # #对list1进行排序 排序之后不改变id号
 # list1.sort()
 # print(list1)#[1, 2, 2, 3, 3, 4, 4, 5, 5]
 # print(id(list1))#43689032

import os
#fork不支持windows上面运行
if __name__ == '__main__':
    pid = os.fork()
    print(pid)