@echo off
setlocal enabledelayedexpansion

:: 逐行读取1.txt文件并统计每行中A的个数
for /f "delims=" %%a in (1.txt) do (
    set "line=%%a"
    set "count=0"
    :: 使用for循环和参数修饰符来统计A的个数
    for /f "delims=" %%i in ('echo !line! | findstr /r /i /c:"A"') do set /a count+=1
    echo !count!
)

endlocal
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@echo off
setlocal enabledelayedexpansion
for /f "delims=" %%i in (1.txt) do (
    set n=-1
    set "Line="#%%i#""
    set "Line=!Line:a=" "!"
    for %%j in (!line!) do set /a n+=1
    echo,!n!
)
pause
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@echo off &setlocal
for /f "delims=" %%a in (1.txt) do (
	echo,%%a>0.0&for %%v in (0.0) do set "v1=%%~zv"
	setlocal enabledelayedexpansion &set "s=%%a" &set "s=!s:a=!"
	echo,!s!>0.0&for %%v in (0.0) do set "v2=%%~zv"
	set/a "v=v1-v2" &echo,本行包含字符 a 的数量 = !v!&endlocal
)
del/q "0.0"&endlocal&pause&exit/b
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@echo off &setlocal
for /f "delims=" %%a in (1.txt) do (
	echo,%%a>0.0&for %%v in (0.0) do set "v1=%%~zv"
	echo,%%a|sed "s/a//g">0.0&for %%v in (0.0) do set "v2=%%~zv"
	for /f %%v in ('set/a v1-v2') do (echo,本行包含字符 a 的数量 = %%v)
)
del/q "0.0"&endlocal&pause&exit/b
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如源文件中有被双引号包裹的字段，典型格式如 *.csv 文本行，例如：
"qwe",00,"A",23,"a",45
"a",45,"zxc",22
"asd",11,"aa",34
"AA",33
"xyz",89
二楼代码将会刷零...

gc '1.txt' |where {$_} |foreach {[regex]::matches($_,'(?i)A').count}
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@echo off
call :1
cd /d "%~dp0"
for /f "tokens=1* delims=[]" %%a in ('find /n "a" ^<"1.txt"') do (
	set str=%%b
	setlocal enabledelayedexpansion
	set "$1=!$!!str!!str!!str!"
	set "$2=!$!!str:a=!!str:a=!!str:a=!"
	set /a len=0x!$1:~-3840,3!-0x!$2:~-3840,3!
	echo line:%%a count:!len!
	endlocal
)
pause
exit

	:1
	rem "http://www.bathome.net/redirect.php?goto=findpost&ptid=11799&pid=210336"
	setlocal enabledelayedexpansion
	set a=□0□1□2□3□4□5□6□7□8□9□A□B□C□D□E□F
	set b=□0□1□2□3□4
	set d=!%a:□=!!a:□=□%!
	set $=!%b:□=!!d:□=%!
	endlocal & set $=%$%
	exit /b
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