Regular Expressions List of meta characters: . ---> Any one character ? ---> Zero or one + ---> One or more * ---> zero or more ^ ---> at the beginning of the string $ ---> at the end of the string [abc] ---> any one of a b c {m} ---> 'm' times {m,n} ---> at least m times, at most n times | ---> or \ ---> escape sequence character \s ---> a space \d ---> a digit \w ---> a word \b ---> a word boundary examples: \d ---> a single digit number (0 to 9) \d\d ---> a two digit number (0 to 99) \d\d\d ---> a three digit number (000 to 999) NOTE: ?, +, *, {} are used as Quantifiers (to represent quantity) \d{3} ---> same as above \d{3,5} ---> either 3 digit or 5 digit number hell?o ---> helo | hello hell+o ---> hello | helllo | helllllo | ... hrll*o ---> helo | hello | helllo | helllllo | ... he(ll)+o ---> hello | hellllo | hellllllo | ... S = "hi hello how are hello" hello ---> Yes ^hello ---> No h...
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