Chinaunix首页 | 论坛 | 博客
  • 博客访问: 691065
  • 博文数量: 112
  • 博客积分: 3889
  • 博客等级: 少校
  • 技术积分: 1448
  • 用 户 组: 普通用户
  • 注册时间: 2010-10-19 16:35
个人简介

追求卓越,成功就会在不经意间追上你

文章分类

全部博文(112)

文章存档

2015年(1)

2014年(2)

2013年(1)

2012年(16)

2011年(86)

2010年(6)

分类: Python/Ruby

2011-05-07 13:46:29

for Loop:

Syntax:
for {variable name} in {list}
do
  #do statements untill varibles are out of list
  {statements/commands}
done

e.g. 1:
[fedora@novice shell_scripts]$ cat > testfor.sh
for i in 1 2 3 4 5
do 
   echo "welcome $i time(s)"   
done
[fedora@novice shell_scripts]$ sh testfor.sh
welcome 1 time(s)
welcome 2 time(s)
welcome 3 time(s)
welcome 4 time(s)
welcome 5 time(s)

Another syntax:
for ((expr1;expr2;expr3))
do
  {statements/commands}
  #do statements or commands when expr2 is true
done

e.g. 2:
[fedora@novice shell_scripts]$ cat >testfor1.sh
for ((i=0;i<=5;i++))
do
   echo "Welcome $i time(s)"      
done
[fedora@novice shell_scripts]$ sh testfor1.sh
Welcome 0 time(s)
Welcome 1 time(s)
Welcome 2 time(s)
Welcome 3 time(s)
Welcome 4 time(s)
Welcome 5 time(s)

nested for loop:
e.g.3:
#!/bin/bash
#
#test nested for loop
#

for ((i=1;i<=5;i++))
do
   for((j=1;j<=5;j++))
   do
      echo -n "$i"
   done
   echo ""
done
[fedora@novice shell_scripts]$ sh nestedfor.sh 
11111
22222
33333
44444
55555

e.g. 4:
打印九九乘法表
#!/bin/bash 
#
#print chengfabiao
#
for ((i=1;i<=9;i++))
do
   for ((j=1;j<=i;j++))
   do
      echo -n "$j * $i =`expr $i \* $j` "
   done
   echo ""
done
[fedora@novice shell_scripts]$ sh jiujiu.sh 
1 * 1 =1 
1 * 2 =2 2 * 2 =4 
1 * 3 =3 2 * 3 =6 3 * 3 =9 
1 * 4 =4 2 * 4 =8 3 * 4 =12 4 * 4 =16 
1 * 5 =5 2 * 5 =10 3 * 5 =15 4 * 5 =20 5 * 5 =25 
1 * 6 =6 2 * 6 =12 3 * 6 =18 4 * 6 =24 5 * 6 =30 6 * 6 =36 
1 * 7 =7 2 * 7 =14 3 * 7 =21 4 * 7 =28 5 * 7 =35 6 * 7 =42 7 * 7 =49 
1 * 8 =8 2 * 8 =16 3 * 8 =24 4 * 8 =32 5 * 8 =40 6 * 8 =48 7 * 8 =56 8 * 8 =64 
1 * 9 =9 2 * 9 =18 3 * 9 =27 4 * 9 =36 5 * 9 =45 6 * 9 =54 7 * 9 =63 8 * 9 =72 9 * 9 =81 

下面还提供了一些练习,有兴趣的可以看看:
阅读(751) | 评论(0) | 转发(0) |
0

上一篇:if construction 备忘

下一篇:while case 备忘

给主人留下些什么吧!~~