Batch rounding a number

问题

I have a script that calculates disk space in bytes. I have found a way to convert it to megabytes. I have just run it and i got a this: 1867.603187561035. Is there a way of rounding it is it would be much clearer if it said 1868. Thanks for any help.

回答1:

@echo off
set "number_to_round=1867.603187561035"

for /f "tokens=1,2 delims=." %%a  in ("%number_to_round%") do (
  set first_part=%%a
  set second_part=%%b
)

set second_part=%second_part:~0,1%
echo %second_part%
if defined second_part if %second_part% GEQ 5 ( 

    set /a rounded=%first_part%+1
) else ( 
    set /a rounded=%first_part%
)

echo %rounded%

OR (with the javascript call you can get more precise results and work with long number (while batch is limited to integers))

@echo off
set number_to_round=1867.603187561035

set "beginJS=mshta "javascript:close(new ActiveXObject('Scripting.FileSystemObject').GetStandardStream(1).Write(Math.round(%number_to_round%)"
set "endJS=));""

for /f %%N in (
  '%beginJS%%endJS%'
) do set rounded=%%N

echo %rounded%

回答2:

If you just want get the number before the . :

@echo off

set $value=1867.703187561035

for /f "tokens=1 delims=." %%a in ('echo %$Value%') do set %$number%=%%a

echo %$Number%

And if you really want to test the second part of the number :

@echo off

setlocal EnableDelayedExpansion
set $value=1867.703187561035

for /f "tokens=1,2 delims=." %%a in ('echo %$Value%') do (
set $Number=%%a
set $Vtest=%%b
if "!$Vtest:~0,1!" geq "5" set /a $Number+=1
)

echo !$Number!

回答3:

It would be better if you showed the script in question, but yes, rounding can be performed. We just have to do the process manually. Here is a routine that will take in the number and a variable for the result.

:Round <Input> <Output>
setlocal
for /f "tokens=1,2 delims=." %%A in ("%~1") do set "X=%%~A" & set "Y=%%~B0"
if %Y:~0,1% geq 5 set /a "X+=1"
endlocal & set "%~2=%X%"
exit /b 0

Usage:

@echo off
setlocal
call :Round 12345.6789 Out
echo %Out%
endlocal
exit /b 0

回答4:

Here is a native batch/jscript hybrid posted recently that will
return a MB figure, for a byte figure given as %1 (and not limited to 2GB figures as batch math is)

It does not round up or round down the partial megabyte after the decimal point, it just removes it.

@if (@CodeSection == @Batch) @then

@echo off
set JScall=Cscript //nologo //E:JScript "%~F0"
for /f "delims=." %%a in ('%JScall% "%~1/1024/1024"') do set "size=%%a"
echo %size%
goto :EOF

@end
WScript.Echo(eval(WScript.Arguments.Unnamed.Item(0)));

回答5:

There is an even easier way to round a number to the nearest integer, supposing it is not negative and less than 100000000:

set NUMBER=1867.603187561035

rem // Enforce fractional part:
set NUMBER=%NUMBER%.
rem // Get integer part:
set /A NROUND=NUMBER+0
rem // Extract fractional part:
set NFRACT=%NUMBER:*.=%0
rem /* Prepend `1` to integer part to avoid trouble with leading `0`
rem    (remember that such numbers are interpreted as octal ones);
rem    append first fractional digit to integer part, then add `5`: */
set /A NROUND=1%NROUND%%NFRACT:~,1%+5
rem // Strip off first and last digits and return remaining integer:
if %NROUND:~,1% GTR 1 (echo 1%NROUND:~1,-1%) else (echo %NROUND:~1,-1%)

To round a signed number in the range between −100000000 and +100000000 to the nearest integer, use this code snippet:

set NUMBER=1867.603187561035

rem // Enforce fractional part:
set NUMBER=%NUMBER%.
rem // Get integer part:
set /A NROUND=NUMBER+0
rem // Cache sign and remove it temporarily:
if %NROUND% LSS 0 (set /A NROUND=-NROUND & set SIGN=-) else set SIGN=
rem // Extract fractional part:
set NFRACT=%NUMBER:*.=%0
rem /* Prepend `1` to integer part to avoid trouble with leading `0`
rem    (remember that such numbers are interpreted as octal ones);
rem    append first fractional digit to integer part, then add `5`: */
set /A NROUND=1%NROUND%%NFRACT:~,1%+5
rem // Strip off first and last digits and return remaining integer:
if %NROUND:~,1% GTR 1 (echo %SIGN%1%NROUND:~1,-1%) else (echo %SIGN%%NROUND:~1,-1%)

来源：https://stackoverflow.com/questions/23116014/batch-rounding-a-number

标签

math

batch-file

rounding