To get a list of notes in category #1 try the following:
Get a list of notes
PHP
$d=Data::cache("notes", "view", "list");$d->setValue("catnr", 1); //set the category identifier to the categories reference (catnr by default)
if($d->get())
while($d->next())
print $d->v["name"]."
".$d->v["text"]; //print out the name and text of all notes in category #1
Like with getting items you can omit the "setValue" line to use the "catnr" value provided in the URL to get more dynamic list. Additionally can also set multiple catnr values to get items from multiple categories in one go.