In our last tutorials regarding ReGex we have some simple pattern of matching. We also use caret (^) For matching at the beginning of the string and (\z) to match at the end of the string. These characters are called Meta Characters and shown below.

a. . (Full stop)
b. ^ (Carat)
c. * (Asterix)
d. + (Plus)
e. ? (Question Mark)
f. { (Opening curly brace)
g. [ (Opening brace)
h. ] (Closing brace)
i. \ (Backslash)
g. | (Pipe)
k. ( (Opening parens)
l. ) (Closing parens)
m. } (Closing curly brace)

Above characters are very useful in terms of ReGex. But if you search a character that include with special character of Meta Characters. Then we need to escape it using backslash.

Sample string: 1+2=3

1. <?php
   
2. 
   
3. // create a string
   
4. $string
   
   =
   
   '1+2=3'
   
   ;
   
5. // try to match our pattern
   
6. 
   
7. if
   
   (
   
   preg_match
   
   (
   
   "/^1\+2/i"
   
   ,
   
   $string
   
   )
   
   )
   
   {
   
8. 
   
9. // if the pattern matches we echo this
   
10. echo
    
    'The string begins with 1+2'
    
    ;
    
11. }
    
    else
    
    {
    
12. 
    
13. // if no match is found we echo this line
    
14. 
    
15. echo
    
    'No match found'
    
    ;
    
16. }
    
17. ?>
    

From the code above you will see the script that display:
"The string begins with 1+2" because if found the pattern 1+2 and escape the special meaning of + symbol in Meta characters.
I you would not escape the the character preg_match

(

"/^1+1/i/"

,

$string

)

;

then it will display "No match found".

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