pat atching regul ar xpressions you may be familiar with searching for text by pressing ctrl- and entering the words you're looking for regular expressions go one step furtherthey allow you to specify pattern of text to search for you may not know business' exact phone numberbut if you live in the united states or canadayou know it will be three digitsfollowed by hyphenand then four more digits (and optionallya three-digit area code at the startthis is how youas humanknow phone number when you see it - is phone numberbut , , , is not we also recognize all sorts of other text patterns every dayemail addresses have symbols in the middleus social security numbers have nine digits and two hyphenswebsite urls often have periods and forward slashesnews headlines use title casesocial media hashtags begin with and contain no spacesand more