#!/usr/bin/env python3
# -*- coding:utf-8 -*-

def collatz(number):
 print(number)
 if number ==1:
  return number
 elif number % 2 ==0:
  return collatz(number//2)
 else:
  return collatz(3*number +1)

A = int(input('Input a number: '))
while True:
 if collatz(A) != 1:
  continue
 else:
  break

Input a number: 6
6
3
10
5
16
8
4
2
1

#!/usr/bin/env python3
# -*- coding:utf-8 -*-

def func(spam):
 spam[-1]='and'+ ' ' + spam[-1]
 for i in range(len(spam)):
  print(spam[i], end=',')


spam = ['apple', 'bananas', 'tofu', 'cats', 'dog']
func(spam)
#输出结果
apple,bananas,tofu,cats,and dog,

#!/usr/bin/env python3
# -*- coding:utf-8 -*-

grid = [
 ['.', '.', '.', '.', '.', '.'],
 ['.', 'O', 'O', '.', '.', '.'],
 ['O', 'O', 'O', 'O', '.', '.'],
 ['O', 'O', 'O', 'O', 'O', '.'],
 ['.', 'O', 'O', 'O', 'O', 'O'],
 ['O', 'O', 'O', 'O', 'O', '.'],
 ['O', 'O', 'O', 'O', '.', '.'],
 ['.', 'O', 'O', '.', '.', '.'],
 ['.', '.', '.', '.', '.', '.']]
#嵌套循环
for n in range(len(grid[0])):
 for m in range(len(grid)):
  print(grid[m][n], end='')
 print('\n')#换行

#输出结果
..OO.OO..

.OOOOOOO.

.OOOOOOO.

..OOOOO..

...OOO...

....O....