for循环计数

1、巧用for循环计数，将文件每10行写到另一个文件，每遍历一行i就加1

with open('/etc/passwd') as f1, open('/tmp/passwd','w') as f2:
    i = 0
    for line in f1:
        i += 1
        if i % 10 == 0:
            print line,
            f2.write(line)

2、打印图形

count = 1
while count < 6:
    print count * '*'
    count += 1

for line in range(1,6):
    print line * '*'

for number in range(1,6):
    if number % 2 == 0:
        print 5 * '+'
    else:
        print 5 * '@'

结果:

*
**
***
****
*****
*
**
***
****
*****
@@@@@
+++++
@@@@@
+++++
@@@@@