strpos($wholeText, $findText) in PHP returns position from which the $findText value starts if it is present in $wholeText. If it is not found then this function returns false. Fun starts when text is found at the very beginning (at position 0, as 0 is equivalent to false in PHP if not used with correct operator).
Read the code below and comments to understand different cases.
This is the output of the code below:
Not Found without == or === Not Found with ==true Not Found with === Not Found with !=false Found with !==false Found with ===false Found with ===FALSE
Code :
<?php $value = 'This is a long sentence to test search'; $findme = 'This'; $pos = strpos($value, $findme);//$pos will have value 0 as This starts from 0th position in the string if($pos) { //since $pos is 0 and 0 is considered as false hence this if condition does not work echo 'Found without == or ==='; } else { echo 'Not Found without == or ==='; } if($pos == true) { //$pos is 0 so 0 == true will not work echo 'Found with ==true'; } else { echo 'Not Found with ==true'; } if($pos === true) { //$pos is 0 so 0 === true will not work as both do not match in data type and value echo 'Found with ==='; } else { echo 'Not Found with ==='; } if($pos != false) { // 0 is considered as false hence 0 != false will not work echo 'Found with !=false'; } else { echo 'Not Found with !=false'; } if($pos !== false) { //0 !== false works as it matches data type of values as well and they don't match hence this expression returns true echo 'Found with !==false'; } else { echo 'Not Found with !==false'; } if($pos === false) { //0 === false makes the condition fail as it matches data type of values as well and they don't match hence it returns false and goes to else part hence works echo 'Not Found with ===false'; } else { echo 'Found with ===false'; } if($pos === FALFALSESE) { //0 === false makes the condition fail as it matches data type of values as well and they don't match hence it returns false and goes to else part hence works echo 'Not Found with ===FALSE'; } else { echo 'Found with ===FALSE'; } ?>
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