PHP if statement strpos === false with an or || - php

Question

I'm trying to get the if statement to echo equals true but it equals false. What am I doing wrong?
sometimes $line-2 will be 5% and sometimes it will be 0%. So it varies like that. How would I write the if statement for both cases?
So basically, I want it to echo equal true if the variable line_2 is 0% or is 5%. I only want it to echo equals false if the variable is anything other than 0% or 5%.
$line_2 = '5%'; // this will be random. Can be 0%. Can be 5%. Can be 25%.
if (strpos($line_2, '5') === false || strpos($line_2, '0') === false) {
echo 'equals false';
} else {
echo 'equals true';
}
more clarification.
Where it says echo 'equals false' there is actually a command there to execute another php script. I need that script to be executed only if line_2 does not equal 5% or it does not equal 0%.
Hope that sums it up.

Answer 1

Your problem stems from a misunderstanding of the way you negate conditional statements.
You mention that you want to echo true if $line_2 contains a 0 OR a 5; however, your if statement checks the opposite condition to echo false and will echo true if the condition fails. So we need to change the condition from if line contains 0 or line contains 5 to if not (line contains 0 or line contains 5).
The way you accomplish this is by considering De Morgan's laws. Specifically, when you distribute negation across logical OR or logical AND, the following holds true:
not (A OR B) = (not A) AND (not B)
not (A AND B) = (not A) OR (not B)
That is, you distribute the negation and change the logical operator to its opposite.
In this case, since you want to accomplish not (line contains 0 or line contains 5), you should distribute it such that you obtain (not line contains 0) and (not line contains 5), which looks like this:
$line_2 = '5%'; // this will be random. Can be 0%. Can be 5%. Can be 25%.
if (strpos($line_2, '5') === false && strpos($line_2, '0') === false) {
echo 'equals false';
} else {
echo 'equals true';
}
The problem with your current code is that you instead have a solution resembling if (not line contains 0) or (not line contains 5). The difference between the two is only in the logical operator connecting the two conditions, where you're using or but should really be using and.

Answer 2

Based on OP's edit, you should reverse your if condition check logic. Do the following:
$line_2 = '5%'; // Or it can be 0%
if (strpos($line_2, '5') !== false || strpos($line_2, '0') !== false) {
echo 'equals true'; // 0 or 5 is found in the string
} else {
echo 'equals false';
}

Answer 3

You don't really need strpos() for this unless $line_2 might sometimes contain more strings.
<?php
$line_2 = '5%';
$statement = 'equals false'; //Set the default message
if ($line_2 === '5%' || $line_2 === '%0') { //Check if $line_2 equals 5% or 2%. Note the strong comparison since $line_2 is a string.
$statement = 'equals true';
}
echo $statement;

Answer 4

Use && instead
Using the OR operator in that if statement will return true if that character is '5' OR '0'
So, becausestrpos($line_2, '0') === false will return true, your statement will become
if(false || true)
thus echoing 'equals false', whereas using AND
if(false && true)
will be false, giving you 'equals true'