A basic, basic primer for regex and PHP.

regex-schtuff.txt

 _______                                   ______          __       _              ___    ___  
|_   __ \                                .' ____ \        [  |     / |_          .' ..] .' ..] 
  | |__) |  .---.  .--./) .---.  _   __  | (___ \_| .---.  | |--. `| |-'__   _  _| |_  _| |_   
  |  __ /  / /__\\/ /'`\;/ /__\\[ \ [  ]  _.____`. / /'`\] | .-. | | | [  | | |'-| |-''-| |-'  
 _| |  \ \_| \__.,\ \._//| \__., > '  <  | \____) || \__.  | | | | | |, | \_/ |, | |    | |    
|____| |___|'.__.'.',__`  '.__.'[__]`\_]  \______.''.___.'[___]|__]\__/ '.__.'_/[___]  [___]   
                 ( ( __))                                                                      


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     /\ 
    / / 
   / /  
  / /   
 / /    
 \/     

/  - Delimiter to start and end an expression or can be used as a literal match but must be escaped \/

    Example of delimiter:
		preg_match('/foobar/', 'foobar') - returns true

	Example of escaped literal:
		preg_match('/\//', '/') - returns true

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  __   __   
.' _| |_ `. 
| |     | | 
| |     | | 
| |_   _| | 
`.__| |__,' 
            

() - Parentheses - supplies a regex function with an array of sub-matches - can be nested infinately

	preg_match_all('/foo(bar)/', 'foobar', $matches) - returns an array $matches with the value of 'bar'
	preg_match_all('/foo(ba(r))/', 'foobar', $matches) - returns an array $matches with the value of 'bar' & 'r'

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 ___   ___  
|  _| |_  | 
| |     | | 
| |     | | 
| |_   _| | 
|___| |___| 


[] - Square Brackets - creates a list of things to match i.e. A-Za-z0-9 or any character (escaped if need be)

	Example of matching integers:
		preg_match('/foo[0-5]bar/', 'foo3bar') - returns true

	Example of matching range of alpha chars:
		preg_match('/foo[A-D]bar/', 'fooCbar') - returns true

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   .-.    
 __| |__  
|__   __| 
   | |    
   '-'    
          

+  - Plus - matches a preceeding character 1 or more times

	preg_match('/fo+bar/', 'foobar') - returns true

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  _____   
 / ___ `. 
|_/___) | 
  /  __.' 
  |_|     
  (_)     


?  - Matches preceeding character 0 or 1 times.

	preg_match('/foobar?/', 'fooba') - returns true

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   __   __    
 .' _/ \_ `.  
 | |     | |  
< <       > > 
 | |_   _| |  
 `.__\ /__.'  
              

{} - Curly Brackets - Lets you define a range of n times. i.e. {2} {2,6} (N times between 2 and 6)

	preg_match('/fo{2}b[ar]{1,2}', 'foobar') OR preg_match('/fo{2}b[ar]{1,2}', 'fooba') - returns true

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 _  
| | 
| | 
| | 
| | 
|_| 
    

|  - Pipe - Search for a list of specific strings

	preg_match('/foo(blue|clear|red)bar/', 'fooclearbar') - returns true

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  ___   
 / _ \  
|_/ \_| 


^  - Caret - Start of line or negation of expression (everything except)

	Example of start of line:
		preg_match('/^foobar/', 'foobar') - returns true

	Example of expression negation:
		preg_match('/[^foobar]{6} I Love You/', 'foobar I Love You') - returns false
		preg_match('/[foobar]{6} I Love You/', 'foobar I Love You') - returns true

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   ,--.   
 ,-|  |-. 
|  |  |-' 
 '-|  |`\ 
.--|  | / 
`--|  |'  
   `--'   

$  - Dollar Sign - look at the end of a line

	preg_match('/^foobar$/', 'foobar') - returns true

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 _  
(_) 
    

.  - Matches any character

	preg_match('/^.+$/', 'foobar') - returns true (all chars between BOL and EOL)

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