How do you get the string length in a batch file

Question

There doesn t appear to be an easy way to get the length of a string in a batch file   E g    SET MY STRING abcdefg SET  A MY STRING LEN       How would I find the string length of MY STRING   Bonus points if the string length function handles all possible characters in strings including escape characters  like this

User · Answer

If you insist on having this trivial function in pure batch I suggest this:

@echo off

set x=somestring
set n=0
set m=255

:loop
if "!x:~%m%,1!" == "" (
    set /a "m>>=1"
    goto loop
) else (
    set /a n+=%m%+1
    set x=!x:~%m%!
    set x=!x:~1!
    if not "!x!" == "" goto loop
)

echo %n%

PS. You must have delayed variable expansion enabled to run this.

EDIT. Now I have made an improved version:

@echo off

set x=somestring
set n=0

for %%m in (4095 2047 1023 511 255 127 63 31 15 7 3 1 0) do (
    if not "!x:~%%m,1!" == "" (
        set /a n+=%%m+1
        set x=!x:~%%m!
        set x=!x:~1!
        if "!x!" == "" goto done
    )
)

:done
echo %n%

EDIT2. If you have a C compiler or something on your system you can create the programs you need and miss on the fly if they don't exist. This method is very general. Take string length as an example:

@echo off

set x=somestring

if exist strlen.exe goto comp
echo #include "string.h" > strlen.c
echo int main(int argc, char* argv[]) { return strlen(argv[1]); } >> strlen.c
CL strlen.c 

:comp
strlen "%x%"
set n=%errorlevel%
echo %n%

You have to set up PATH, INCLUDE and LIB appropriately. This too can be done on the fly from the batch script. Even if you don't know whether you've got a compiler or don't know where it is you can search for it in your script.

User · Answer

It s Much Simplier   Pure batch solution  No temp files  No long scripts    echo off setlocal enabledelayedexpansion set String abcde12345  for  L   x in  1 1 1000  do   if   String    x       set Lenght   x  amp  goto Result     Result  echo Lenght   Lenght    1000 is the maximum estimated string lenght  Change it based on your needs

User · Answer

I prefer jeb s accepted answer - it is the fastest known solution and the one I use in my own scripts   Actually there are a few additional optimizations bandied about on DosTips  but I don t think they are worth it   But it is fun to come up with new efficient algorithms  Here is a new algorithm that uses the FINDSTR  O option    echo off setlocal set  test Hello world       Echo the length of TEST call  strLen test     Store the length of TEST in LEN call  strLen test len echo len  len  exit  b   strLen  strVar   rtnVar  setlocal disableDelayedExpansion set len 0 if defined   1 for  f  delims      N in        cmd  v on  c echo    1  amp echo   findstr  o        do set  a  len   N-3  endlocal  amp  if    2  neq     set   2  len   else echo  len  exit  b   The code subtracts 3 because the parser juggles the command and adds a space before CMD  V  C executes it  It can be prevented by using  echo    1          For those that want the absolute fastest performance possible  jeb s answer can be adopted for use as a batch  macro  with arguments  This is an advanced batch technique devloped over at DosTips that eliminates the inherently slow process of CALLing a  subroutine  You can get more background on the concepts behind batch macros here  but that link uses a more primitive  less desirable syntax   Below is an optimized  strLen macro  with examples showing differences between the macro and  subroutine usage  as well as differences in performance    echo off setlocal disableDelayedExpansion     -------- Begin macro definitions ---------- set   LF      This creates a variable containing a single linefeed  0x0A  character          Define   n  to effectively issue a newline with line continuation set    n     LF  LF   LF  LF          strLen  StrVar   RtnVar          Computes the length of string in variable StrVar      and stores the result in variable RtnVar       If RtnVar is is not specified  then prints the length to stdout     set  strLen for     in  1 2  do if      2    n    for  f  tokens 1 2 delims       1 in    argv    do   endlocal  n      set  s A    1    n      set  len 0   n      for   P in  4096 2048 1024 512 256 128 64 32 16 8 4 2 1  do    n        if   s    P 1   neq       n          set  a  len    P   n          set  s  s    P    n           n         n      for   V in   len   do endlocal  amp if     2  neq     set     2   V   else echo   V  n       n    else setlocal enableDelayedExpansion  amp setlocal  amp set argv       -------- End macro definitions ----------     Print out definition of macro set  strLen     Demonstrate usage  set  testString this has a length of 23   echo  echo Testing    strLen   testString   strLen  testString  echo  echo Testing call  strLen testString call  strLen testString  echo  echo Testing    strLen   testString rtn set  rtn     strLen  testString rtn echo rtn  rtn   echo  echo Testing call  strLen testString rtn set  rtn   call  strLen testString rtn echo rtn  rtn   echo  echo Measuring    strLen   time  set  t0  time   for  l   N in  1 1 1000  do   strlen  testString testLength set  t1  time   call  printTime  echo  echo Measuring CALL  strLen time  set  t0  time   for  l   N in  1 1 1000  do call  strLen testString testLength set  t1  time   call  printTime exit  b    strlen  StrVar   RtnVar        Computes the length of string in variable StrVar    and stores the result in variable RtnVar     If RtnVar is is not specified  then prints the length to stdout         setlocal EnableDelayedExpansion   set  s A   1     set  len 0    for   P in  4096 2048 1024 512 256 128 64 32 16 8 4 2 1  do       if   s    P 1   neq            set  a  len    P        set  s  s    P                   endlocal   if    2  equ     echo  len   else set    2  len     exit  b     printTime setlocal for  f  tokens 1-4 delims        a in    t0   0    do set  a  t0    1  a 60  1  b  60 1  c  100 1  d-36610100 for  f  tokens 1-4 delims        a in    t1   0    do set  a  t1    1  a 60  1  b  60 1  c  100 1  d-36610100 set  a tm t1-t0 if  tm  lss 0 set  a tm  24 60 60 100 echo  tm  0 -2   tm  -2  msec exit  b   -- Sample Output --   strLen for    in  1 2  do if     2     for  f  tokens 1 2 delims      1 in    argv    do   endlocal     set  s A   1       set  len 0      for  P in  4096 2048 1024 512 256 128 64 32 16 8 4 2 1  do         if   s   P 1   neq              set  a  len   P          set  s  s   P                     for  V in   len   do endlocal amp if    2  neq     set    2  V   else echo  V       else setlocal enableDelayedExpansion amp setlocal amp set argv    Testing   strLen  testString 23  Testing call  strLen testString 23  Testing   strLen  testString rtn rtn 23  Testing call  strLen testString rtn rtn 23  Measuring   strLen  time  1 93 msec  Measuring CALL  strLen time  7 08 msec

User · Answer

echo off  amp  setlocal EnableDelayedExpansion set Var finding the length of strings for  l   A in  0 1 10000  do if not   Var      Var  0   A    set  a Length  1  else  echo  Length   amp  pause  amp  exit  b    set the var to whatever you want to find the length of it or change it to set  p var  so that the user inputs it  Putting this here for future reference

User · Answer

You can do it in two lines  fully in a batch file  by writing the string to a file and then getting the length of the file  You just have to subtract two bytes to account for the automatic CR LF added to the end   Let s say your string is in a variable called strvar   ECHO  strvar  gt  tempfile txt FOR     IN  tempfile txt  DO   SET  A strlength    z  - 2     The length of the string is now in a variable called strlength   In slightly more detail    FOR     IN  filename  DO         gets info about a file SET  A  variable   expression    evaluate the expression numerically    z    Special expression to get the length of the file     To mash the whole command in one line   ECHO  strvar  gt x amp FOR     IN  x  DO SET  A strlength    z  - 2 amp del x

User · Answer

Just another batch script to calculate the length of a string  in just a few lines  It may not be the fastest  but it s pretty small  The subroutine   len  returns the length in the second parameter  The first parameter is the actual string being analysed  Please note - special characters must be escaped  that is the case with any string in the batch file    echo off setlocal call  len  Sample text  a echo The string has  a  characters  endlocal goto  eof   len  lt string gt   lt length variable gt  - note  string must be quoted because it may have spaces setlocal enabledelayedexpansion amp set l 0 amp set str   1  len loop set x  str   l  1  amp if not defined x  endlocal amp set    2  l   amp goto  eof  set  a l  l  1 amp goto  len loop

User · Answer

echo off      warning doesn t like     in mystring  setlocal enabledelayedexpansion   set mystring this is my string to be counted forty one  call  getsize  mystring  echo count  count  of   mystring     set mystring this is my string to be counted  call  getsize  mystring   echo count  count  of   mystring     set mystring this is my string call  getsize  mystring   echo count  count  of   mystring    echo  pause goto  eof     Get length of mystring line           subroutine getsize            getsize  set count 0  for  l   n in  0 1 2000  do        set chars       set chars  mystring    n       if defined chars set  a count  1   goto  eof                    end of subroutine getsize

User · Answer

If you are on Windows Vista    then try this Powershell method   For  F   L in   Powershell  Env MY STRING Length   do       Set MY STRING LEN   L     or alternatively   Powershell  Env MY STRING Length  gt   Temp  TmpFile txt Set  p MY STRING LEN    lt   Temp  TmpFile txt Del  Temp  TmpFile txt   I m on Windows 7 x64 and this is working for me

User · Answer

As there is no built in function for string length  you can write your own function like this one     echo off setlocal REM     Some tests  to check the functionality     REM     An emptyStr has the length 0 set  emptyString   call  strlen result emptyString echo  result   REM     This string has the length 14 set  myString abcdef           call  strlen result myString echo  result   REM     This string has the maximum length of 8191 setlocal EnableDelayedExpansion set  long    FOR  L   n in  1 1 13  DO set  long  long  -4000  long  -4000    set  longString  long  long  -191    call  strlen result longString echo  result   goto  eof  REM           function                                strlen  lt resultVar gt   lt stringVar gt           setlocal EnableDelayedExpansion      set  tmp    2       if defined tmp           set  len 1          for   P in  4096 2048 1024 512 256 128 64 32 16 8 4 2 1  do               if   tmp    P 1   NEQ                       set  a  len    P                  set  tmp  tmp    P                                 ELSE           set len 0                endlocal     set    1  len       exit  b     This function needs always 13 loops  instead of a simple strlen function which needs strlen-loops  It handles all characters   The strange expression  set  tmp    2   is necessary to handle ultra long strings  else it s not possible to copy them

User · Answer

I like the two line approach of jmh gr   It won t work with single digit numbers unless you put    around the portion of the command before the redirect  since 1 gt  is a special command  Echo is On  will be redirected to the file   This example should take care of single digit numbers but not the other special characters such as  lt  that may be in the string    ECHO  strvar   gt  tempfile txt

User · Answer

You can try this code  Fast  you can also include special characters   echo off set  str  string   echo  str   gt    tmp  STR  for   P in    TMP  STR   do  set  a strlen    zP-3  echo String lenght   strlen

User · Answer

Just found ULTIMATE solution   set  MYSTRING abcdef            echo   MYSTRING    amp  echo     findstr  O     more  1    set  P RESULT   amp  call exit  B   RESULT    set  A STRLENGTH  ERRORLEVEL -5 echo string   MYSTRING   length    STRLENGTH    The output is   string  abcdef          length   14   It handles escape characters  an order of magnitude simpler then most solutions above  and contains no loops  magic numbers  DelayedExpansion  temp files  etc   In case usage outside batch script  mean putting commands to console manually   replace   RESULT   key with  RESULT    If needed   ERRORLEVEL  variable could be set to FALSE using any NOP command  e g  echo   gt nul

User · Answer

Yes  of course there s an easy way  using vbscript  or powershell     WScript Echo Len  WScript Arguments 0      save this as strlen vbs and on command line  c  test gt  cscript   nologo strlen vbs  abcd    Use a for loop to capture the result   or use vbscript entirely for your scripting task   Certainly beats having to create cumbersome workarounds using batch and there s no excuse not to use it since vbscript is available with each Windows distribution   and powershell in later

User · Answer

ECHO OFF  SET string  SET  A stringLength 0   CheckNextLetter REM Subtract the first letter and count up until the string     IF   string   NEQ          SET string  string  1      SET  A stringLength  stringLength  1     GOTO  CheckNextLetter   ELSE       GOTO  TheEnd     TheEnd     ECHO There is  stringLength  character  s   in the string  PAUSE   This works for me   Hope this is useful for someone else   No need to adjust for any length   I just remove the first letter and compare against    until the string equals

User · Answer

The first few lines are simply to demonstrate the  strLen function     echo off set  strToMeasure This is a string  call  strLen strToMeasure strlen echo String is  strlen  characters long exit  b   strLen setlocal enabledelayedexpansion  strLen Loop   if not    1   len        set  A len  1  amp  goto  strLen Loop  endlocal  amp  set  2  len   goto  eof   Of course  this is not quite as efficient at the  13 loop  version provided by jeb  But it is easier to understand  and your 3GHz computer can slip through a few thousand iterations in a small fraction of a second

User · Answer

I want to preface this by saying I don t know much about writing code script etc  but thought I d share a solution I seem to have come up with  Most of the responses here kinda went over my head  so I was curious to know if what I ve written is comparable    echo off  set stringLength 0  call stringEater  It counts most characters  echo  stringLength  echo  amp pause amp goto eof   stringEater set var   1  subString set n  var  0 1  if   n                 goto eof       else if   n                  set  a stringLength  stringLength  1       else           set  a stringLength  stringLength  1       set var  var  1 1000  if   var                 goto eof       else           goto subString        goto eof

[windows] How do you get the string length in a batch file?

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