can someone explain this regular expression?
this regular expression:
Code:
^(\d+)x(\d+)(?:\+(\d+))?(?:\+(\d+))?$
works for the original intention of matching X11 command -geometry= values. now,i want to change it to match some other strings. but, i don't understand the extra layering of () and what the ? are doing to it. can someone who knows this explain it?
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