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Chapter 10.1.2 RegEx (Regular Expressions (specific commands prompt the…

- - - - noting the difference between digits, whole words, sentences, or phone numbers from random numbers
      - any text that has a predictable format
    - - use escape character \ to specify a special command
        
        abc - a three letter word
        
        \abc - looks for words that start with a and end with c thats 3 letters long
        
        d - a digit
        
        \d - look for a digit
        
        \d\d\d - any combination of 3 digits
        
        \D looks for characters except for digits (letters and puncuation)
        
        \w - looks for any alpha numeric character (0-9) (a-z)
        
        \W non-alpha numeric characters
      - lots of characters have parameters
        
        the '.' doesn't!
        
        colou?r - the ? denotes the u as not necessary for a match
        
        \s white space
        
        \S anything but white space
        
        [abc] specification of a list of allowable characters for a specific character position
        
        so [37]\d\d looks for 3 digit numbers starting with 3 or 7 followed by 2 more digits
        
        [a-z] looks for a range between lowercase a through lowercase z
        
        [^ab] anything but a and b
        
        [apples | bananas] the | is "or" , looks for apples or bananas in the string
        
        ^ab caret outside brackets indicates beginning of string (finds abc not cab)
        
        repetitions - specifies the number of times the searched-for pattern will repeat
        
        \w* - match a letter 0-infinity number of times
        
        \w+ - at least 1 has to occur (1-infinity)
        
        curly brackets z{2,3} finds wazzup (2 z's) but not wazup (only 1 z)
        
        captures - explicit notation of a substring that can be extracted as a new column for machine learning