Recursively Iterating through Directories in Batch - batch-file

Question

Here's the situation:
I have a folder with lots of sub-folders with pdf files. I want to make a batch script that goes through each sub-folder and zip the pdf files if there are over 100 of them (using 7Zip, not asking for help with that part).
This is my first time dealing with windows batch scripting and I am extremely discourage. I have spent hours on Google and I don't think I'm any wiser on the subject. I have found a lot of reference material and example code but not a whole lot of word by word breakdown on examples. I find the syntax to be extremely user unfriendly.
Anyways here's what I've got:
#echo off
for /r %%A in (.) do (
set pdfCount = "Code that gets the total number of pdf files in current directory, something like dir *.pdf?"
if pdfCount GEQ 100 (
set beginDate = "Code that gets the date of the oldest pdf, use in the zip file name"
set endDate = "Code that gets the date of the newest pdf, use in the zip file name"
"Use a 7Zip command to zip the files, I am not asking for help with this code"
DEL *.pdf
echo %pdfcount% files zipped in "Code for current directory"
)
)
pause
My understanding is that "for /r %%A in (.) do ()" is supposed to do execute the code in every sub-directory.

Answer 1

This script is locale dependent, meaning it depends on the way dates and times are formatted on your machine. My machine uses mm/dd/yyyy hh:mm am format. The script will create zip files with names in the form of PDF yyyy_mm_dd yyyy_mm_dd.7z.
#echo off
setlocal disableDelayedExpansion
for /r /d %%P in (*) do (
set "beg="
set /a cnt=0
pushd "%%P"
for /f "eol=: delims=" %%F in ('dir /b /a-d /od *.pdf 2^>nul') do (
set /a cnt+=1
set "end=%%~tF"
if not defined beg set "beg=%%~tF"
)
setlocal enableDelayedExpansion
if !cnt! gtr 100 (
for /f "tokens=1-6 delims=/ " %%A in ("!beg:~0,10! !end!") do (
7zip a "PDF %%C_%%A_%%B %%F_%%D_%%E.7z" *.pdf
del *.pdf
)
)
endlocal
popd
)

Answer 2

This may work. It's not destructive and atm just echoes the 7zip and parameters to the screen.
#echo off
for /f "delims=" %%a in ('dir /b /ad /s') do (
pushd "%%a"
for /f %%b in ('dir *.pdf /b ^|find /c /v "" ') do (
if %%b GTR 100 echo 7zip a "%%~nxa.7z" "*.pdf"
)
popd
)
It takes all the folders in the current directory tree, pushes the directory on the stack to make it current, uses dir and find to count the PDF files, and if the result is greater than 100 it will echo the line to the console. And popd pops the directory off the stack again. The 7z files will be created in the folder with the PDF files and they get the folders name.7z , unless you specify a location for them.