如何在环境变量里边一次读取2个变量？

晨想

这样一个环境变量：
$a = "1 a 2 b 3 c"

我想在用for/while循环里边，一次读取2个值，放入2个变量中。怎么弄？

比如第1次循环， $x = 1, $y = a
　　第2次循环， $x = 2, $y = b
这样

read 似乎不能从 环境变量 中读取内容，郁闷了。

哪位帮一下。。谢谢。

yongjian

put "\n" on each two of them should work

晨想

谢谢，，还是用perl解决算了。。。：）。。

Iambitious

or maybe this code can work well

2. count=0
3. for item in $a;
4. do
5.         let 'count=count+1'
6.         if [ $count -eq 1 ];then
7.                 x=$item
8.                 count=0
9.                 echo $x
10.         else
11.                 y=$item
12.                 echo $y
13.         fi
14. done

复制代码

yongjian

Post by Iambitious
or maybe this code can work well

2. count=0
3. for item in $a;
4. do
5.         let 'count=count+1'
6.         if [ $count -eq 1 ];then
7.                 x=$item
8.                 count=0
9.                 echo $x
10.         else
11.                 y=$item
12.                 echo $y
13.         fi
14. done

复制代码

I doubt. First of all, loop still bases on step 1. you are not reading 2 at a time. Second, I do not think you can have y assigned even though you set count to 0 but that if test has been done.

晨想

谢谢大家的好意，还是用perl算了。能解决问题就好。

Iambitious

yeah you are right.
the code still run step by step, but in truth it can take the same effect.
there are some bugs in my code because I did not test it well. That's my fault.
the rivision is below:

2. count=1
4. for item in $a;
5. do
6.         let 'count=count+1'
7.         if [ $count -eq 2 ];then
8.                 x=$item
9.                 count=0
10.                 echo "x:$x"
11.         else
12.                 y=$item
13.                 echo "y:$y"
14.         fi
15. done

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here is the results:
x:1
y:a
x:2
y:b
x:3
y:c
x:4
y:d

seamonkey

a=(1 a 2 b 3 c)
x=1
y=2
while [[ -n $a[$x] ]]; do
echo $a[$x] $a[$y]
x=$((x+2))
y=$((y+2))
done

Iambitious

Post by seamonkey
a=(1 a 2 b 3 c)
x=1
y=2
while [[ -n $a[$x] ]]; do
echo $a[$x] $a[$y]
x=$((x+2))
y=$((y+2))
done

楼上的程序有几个小毛病：
a=(1 a 2 b 3 c)
x=0
y=1
while [[ -n ${a[$x]} ]]; do
echo ${a[$x]} ${a[$y]}
x=$((x+2))
y=$((y+2))
done
这样就可以了。