Naming convestion for the .xlsx file

[vivek151189]

The colon is not working in the name of .xlsx file
when I use it without colon is fine but when i add colon I get don't get my excel fil generated
I am adding this colon to show time at which it has being generated

$created = date('d-m-Y H:i:s', time());
$file_path = $file_path.$result_group["correct_label"]."_".$created.".xlsx";

how ever I read the document that tell u should avoid this
\ (backslash)
/ (forward slash)
: (colon)
* (asterisk),
? (question mark)
" (double quotes)
< (left angle bracket)

(right angle bracket)
| (pipe)
you can read the dcument Here

so what should I use in place of that i don't want to use underscore
and don't want to use the timestamp the time should be in common man readable form
any suggestion will be appreciated

[Derokorian]

Well for my log files I use:

$l = date('Y-m-d+H-i-s');

Of course I always avoid spaces in names as well. I use descending format like ISO so I can sort the files by created date much easier since its just the file name.

[vivek151189]

would follow your instruction