It is recommended to use the format if defined varName to judge whether a variable is empty, because in many cases, the judgment of if "var" == "" may be wrong due to the variable containing special values.
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中国DOS联盟论坛 » DOS批处理 & 脚本技术（批处理室） » Ask: How to judge that the input variable is empty.
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Posted 2006-12-11 07:02 · 中国 湖北 荆门 电信
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Posted 2006-12-12 01:59 · 中国 浙江 杭州 电信
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The method above can only judge whether the variable exists, but it seems it can't judge whether the variable is empty. I tried:
set B=
if defined B (echo B dump) else (echo full)
The result shows full. Can you explain it in detail?
set B=
if defined B (echo B dump) else (echo full)
The result shows full. Can you explain it in detail?
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Posted 2006-12-12 02:14 · 中国 北京 联通
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defined is to determine whether a variable is defined, regardless of its value. The test result of the upstairs was originally correct.
@echo off&setlocal
set b=hello
set b
if defined b (echo YES) else (echo NO)
pause
set b=
set b
if defined b (echo YES) else (echo NO)
pause
@echo off&setlocal
set b=hello
set b
if defined b (echo YES) else (echo NO)
pause
set b=
set b
if defined b (echo YES) else (echo NO)
pause
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Posted 2006-12-12 02:16 · 中国 河北 廊坊 三河市 移动
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So it turns out that Brother 9527 has joined KFC! ^_^
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Posted 2006-12-12 02:23 · 中国 浙江 杭州 电信
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Originally posted by 9527 at 2006-12-12 02:14 AM:
defined is to determine whether a variable is defined, regardless of what value it has. The test result of the upstairs is originally correct
@echo off&setlocal
set b=hello
set b
if defined b (echo YES) else (echo NO)
p ...
Mistakenly reversed the echo.
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