Such a condition:
<?php $age = '20'; if ($age>=15 && $age<=19) { echo "ะะ"; } ?> Why in the case of && and if you change to & , it will not output anything? What is the difference between these operators?
But if
Dmitriy Simushev
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Beginner beginner
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1 answer
&& is the logical "AND"
It works like this: C = A && B
โญโโโโโโโโโโโโโฌโโโโโโโโโโโโโโฌโโโโโโโโโโโโโโฎ โ A โ B โ C โ โโโโโโโโโโโโโโชโโโโโโโโโโโโโโชโโโโโโโโโโโโโโก โ true โ true โ true โ โ true โ false โ false โ โ false โ true โ false โ โ false โ false โ false โ โโโโโโโโโโโโโโดโโโโโโโโโโโโโโดโโโโโโโโโโโโโโ & is a bitwise "and". It works like this:
C = A & B
A and B are decomposed into a bit representation. Suppose A = 12, and B = 23, then (we count them as bytes)
A=00001100 B=00010111After that, a logical AND is applied to each pair of corresponding data bits A and B (see table above)
A = 0 0 0 0 1 1 0 0 B = 0 0 0 1 0 1 1 1 C = 0 0 0 0 0 1 0 0 = 3
Therefore, 12 & 23 = 3
Now, as for your case. PHP is a language with dynamic typing, hence all the "magic".
$age>=15 && $age<=19 - everything is clear, I hope? Returns true if $ age is between 15 and 19.
$age>=15 & $age<=19 . What happens here? It's simple, first two comparisons are performed, because y >= and <= priority is higher, these comparisons return boolean values: true and false. Then comes the & operator queue, but it does not work with a logical type, so first true=>1 and false=>0 converted, the bitwise ะ is applied to these values โโand the result is converted back to a boolean value, 0 to false and 1 to true.
rjhdby rjhdby
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&&- logical operator,&- bitwise - Alexey Shimansky$age>=15 && $age<=19and$age>=15 & $age<=19in your example will return the same result (the difference is only in the type of value). Proof: ideone.com/crHmAj A question about anything! - Dmitriy Simushev