them even though most modern text editors and word processorssuch as microsoft word or openofficehave find and find-and-replace features that can search based on regular expressions regular expressions are huge time-saversnot just for software users but also for programmers in facttech writer cory doctorow argues that we should be teaching regular expressions even before programmingknowing [regular expressionscan mean the difference between solving problem in steps and solving it in , steps when you're nerdyou forget that the problems you solve with couple keystrokes can take other people days of tediouserror-prone work to slog through in this you'll start by writing program to find text patterns without using regular expressions and then see how to use regular expressions to make the code much less bloated 'll show you basic matching with regular expressions and then move on to some more powerful featuressuch as string substitution and creating your own character classes finallyat the end of the you'll write program that can automatically extract phone numbers and email addresses from block of text finding patterns of text without regular expressions say you want to find an american phone number in string you know the pattern if you're americanthree numbersa hyphenthree numbersa hyphenand four numbers here' an examplelet' use function named isphonenumber(to check whether string matches this patternreturning either true or false open new file editor tab and enter the following codethen save the file as isphonenumber pydef isphonenumber(text)if len(text! return false for in range( )if not text[iisdecimal()return false if text[ !'-'return false for in range( )if not text[iisdecimal()return false if text[ !'-'return false cory doctorow"here' what ict should really teach kidshow to do regular expressions,guardiandecember /dec/ /ict-teach-kids-regular-expressions