如何在DOS批处理文件中实现逻辑操作符?
当前回答
如果你需要else子句,你可以使用下面的语法:
AND:
if %v1% == a (if %v2% == b (echo yes) else echo no) else echo no
OR:
if %v1% == a (echo yes) else (if %v2% == b (echo yes) else echo no)
其他回答
Athul Prakash (age 16 at the time) gave a logical idea for how to implement an OR test by negating the conditions in IF statements and then using the ELSE clause as the location to put the code that requires execution. I thought to myself that there are however two else clauses usually needed since he is suggesting using two IF statements, and so the executed code needs to be written twice. However, if a GOTO is used to skip past the required code, instead of writing ELSE clauses the code for execution only needs to be written once.
下面是一个可测试的例子,我将如何实现Athul Prakash的否定逻辑来创建一个OR。
在我的例子中,如果某人有坦克执照或者正在服兵役,他就可以开坦克。在两个提示中输入true或false,你将能够看到逻辑是否允许你驾驶坦克。
@ECHO OFF
@SET /p tanklicence=tanklicence:
@SET /p militaryservice=militaryservice:
IF /I NOT %tanklicence%==true IF /I NOT %militaryservice%==true GOTO done
ECHO I am driving a tank with tanklicence set to %tanklicence% and militaryservice set to %militaryservice%
:done
PAUSE
对Andry的回答进行了轻微修改,减少了重复的类型命令:
set "A=1" & set "B=2" & call :IF_AND
set "A=1" & set "B=3" & call :IF_AND
set "A=2" & set "B=2" & call :IF_AND
set "A=2" & set "B=3" & call :IF_AND
echo.
set "A=1" & set "B=2" & call :IF_OR
set "A=1" & set "B=3" & call :IF_OR
set "A=2" & set "B=2" & call :IF_OR
set "A=2" & set "B=3" & call :IF_OR
goto :eof
:IF_OR
(if /i not %A% EQU 1 (
if /i not %B% EQU 2 (
echo FALSE-
type 2>nul
)
)) && echo TRUE+
goto :eof
:IF_AND
(if /i %A% EQU 1 (
if /i %B% EQU 2 (
echo TRUE+
type 2>nul
)
)) && echo FALSE-
goto :eof
OR有点棘手,但也不过分。这里有一个例子
set var1=%~1
set var2=%~2
::
set or_=
if "%var1%"=="Stack" set or_=true
if "%var2%"=="Overflow" set or_=true
if defined or_ echo Stack OR Overflow
如果你需要else子句,你可以使用下面的语法:
AND:
if %v1% == a (if %v2% == b (echo yes) else echo no) else echo no
OR:
if %v1% == a (echo yes) else (if %v2% == b (echo yes) else echo no)
许多人似乎忽略了OR最明显的解决方案,即使用标签。
if "%a%" == "ONE" goto do_thing
if "%a%" == "TWO" (
:do_thing
echo a is equal to ONE or TWO
)
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