两个问题，有点长，望不吝赐教
for %%a in (*.txt) do (command)语句中
1. %%a被赋值时，是取出当前目录下文件名与*.txt进行匹配，若能匹配则将其赋予%%a吗，还是*取尽所有可能的字符(串)(毕竟文件名长度是有限的)，然后再判断当前目录下是否存在*.txt文件，若存在则将其赋值给%%a(个人认为第二种情况不太可能，运算量太大)
2.(重点)赋值顺序为何?(我注意到是与dir时列表顺序相同) 在何种条件下退出循环??(似乎并不是一次遍历完当前目录中.txt文件后就退出)
对此小弟自己做了以下测试，以下是测试结果:
说明：当前目录下存在1.txt,2.txt,3.txt三个文档文件(XP系统)
测试代码:@echo off
for %%a in (*.txt) do (
pause
echo .........................................
echo %%a
type %%a>temp.txt
pause
del %%a
pause
ren temp.txt %%~na.txt
echo GET VALUE!!!!!!!!!!!!!!!!!!!
pause
)
echo over-------------------------------------------------------
pause
Press any key to continue . . .
.......................................
1.txt
Press any key to continue . . .
Press any key to continue . . .
GET VALUE!!!!!!!!!!!!!!!!!!!
Press any key to continue . . .
Press any key to continue . . .
.......................................
3.txt
Press any key to continue . . .
Press any key to continue . . .
GET VALUE!!!!!!!!!!!!!!!!!!!
Press any key to continue . . .
Press any key to continue . . .
.......................................
2.txt
Press any key to continue . . .
Press any key to continue . . .
GET VALUE!!!!!!!!!!!!!!!!!!!
Press any key to continue . . .
Press any key to continue . . .
.......................................
1.txt
Press any key to continue . . .
Press any key to continue . . .
GET VALUE!!!!!!!!!!!!!!!!!!!
Press any key to continue . . .
over-----------------------------------
Press any key to continue . . .
（不好意思，不知道怎样贴图片上来<img src="images/smilies/face-laugh.png" align="absmiddle" border="0">）
可见1.txt被两次赋予%%a,虽然这两个1.txt确实是不同的文件，但是2.txt,3.txt应该也是一样啊，难道for是在再次取到相同的参数时就退出吗？？(另外我还注意到，在多次执行时，赋值顺序是比较有规律的，1321->3213->2132……)
若此时我再新建一个文件4.txt，执行结果为
Press any key to continue . . .
.........................................
1.txt
Press any key to continue . . .
Press any key to continue . . .
GET VALUE!!!!!!!!!!!!!!!!!!!
Press any key to continue . . .
Press any key to continue . . .
.........................................
3.txt
Press any key to continue . . .
Press any key to continue . . .
GET VALUE!!!!!!!!!!!!!!!!!!!
Press any key to continue . . .
Press any key to continue . . .
.........................................
2.txt
Press any key to continue . . .
Press any key to continue . . .
GET VALUE!!!!!!!!!!!!!!!!!!!
Press any key to continue . . .
Press any key to continue . . .
.........................................
1.txt
Press any key to continue . . .
Press any key to continue . . .
GET VALUE!!!!!!!!!!!!!!!!!!!
Press any key to continue . . .
Press any key to continue . . .
.........................................
4.txt
Press any key to continue . . .
Press any key to continue . . .
GET VALUE!!!!!!!!!!!!!!!!!!!
Press any key to continue . . .
over-------------------------------------------------------
Press any key to continue . . .
又说明并不是在再次取到同名文件时退出循环的,至此小弟有些不解，望各位大大不吝赐教，三谢！！！
Last edited by fengwuxzg on 2009-12-19 at 17:47 ]
