batch file passing variable to a text file - variables

Question

ECHO off
FOR /r %%a IN (*) DO (
IF NOT "%pth%"==%%~da%%~pa (
ECHO "%pth%">>Liste.txt
)
SET pth=%%~da%%~pa
)
I want to pass a path just one time; not for every file subdirectories includes. How %pth% string variable can be passed to a text file? Why does this code not work?
Is this code wrong?
FOR /r %%a IN (*) DO (
SET pth=%%~da%%~pa
ECHO %pth%>>Liste.txt
)
The code below works. It passes the paths for each file. If there is files more than one in a subdirectory it passes same path as many as the number o files. I don't want it. I want passing the same path once.
FOR /r %%a IN (*) DO ECHO %%~da%%~pa>>Liste.txt

Answer 1

You haven't told use very clearly (with an example) what you want to do.
Fundamentally, within a block statement (a parenthesised series of statements), the entire block is parsed and then executed. Any %var% within the block will be replaced by that variable's value at the time the block is parsed - before the block is executed - the same thing applies to a FOR ... DO (block).
Hence, IF (something) else (somethingelse) will be executed using the values of %variables% at the time the IF is encountered.
Two common ways to overcome this are 1) to use setlocal enabledelayedexpansion and use !var! in place of %var% to access the changed value of var or 2) to call a subroutine to perform further processing using the changed values.
Hence
#ECHO off
setlocal enabledelayedexpansion
FOR /r %%a IN (*) DO (
IF NOT "!pth!"=="%%~dpa" (
ECHO "!pth!">>Liste.txt
)
SET "pth=%%~dpa"
)
should work (I haven't tried it)
OR
for /r /d %%a in (*) do >>liste.txt echo %%a
which is probably easier (produce a listing of all subdirectories)
Note that %%~da%%~pa is equivalent to %%~dpa
Edited to include required "

Answer 2

#Magoo: Thanks. You show me the right.
The code below is which I want; but "if conditional" does not work: ("!pth!"==%%~dpa) check is always return FALSE I think.
#ECHO off
setlocal enabledelayedexpansion
FOR /r %%a IN (*) DO (
IF NOT "!pth!"==%%~dpa (
ECHO %%~dpa>>Liste.txt
)
SET "pth=%%~dpa"
)
#Magoo: The question is how the code above works like your one line code below:
for /r /d %%a in (*) do >>liste.txt echo %%a
or like written by #MC ND:
dir /ad /s /b >> liste.txt

Answer 3

At last this works. Thanks everyone.
code:
#ECHO off
setlocal enabledelayedexpansion
FOR /r %%a IN (*) DO (
IF NOT "!pth!"=="%%~dpa" (
ECHO %%~dpa>>Liste.txt
)
SET "pth=%%~dpa"
)

Answer 4

dir /ad /s /b >> liste.txt
This should do the same your code trying to do: append all the subfolders into the target file.
The problem with the original code is how the parser handles variables. In batch files, when a line or a block of lines is reached, the parser removes all variable reads, replacing them with its value before executing the code. So, if inside a line/block a variable is changed, this changed value can not be retrieved inside the same line/block as the read operation was removed. The usual way to handle it is to enable delayed expansion. This allows to change where needed variable read syntax from %var% into !var!, indicating to the parser that the read operation must be delayed until the code is executed.
So, in your case, filtering the path of the files
setlocal enabledelayedexpansion
set "pth="
FOR /r %%a IN (*) DO (
IF NOT "!pth!"=="%%~dpa" (
ECHO "%%~dpa">>Liste.txt
SET "pth=%%~dpa"
)
)

Answer 5

Put the IF %pth% condition outside the FOR and it should work.
What exactly do you want to do ? Perhaps theres a simpler way.