How PHP strings are converted to if condition statements

For example: $condition = "2 = = 2 && 3 = = 5";
if ($condition) {
Echo 1;
}
How do I convert a $condition to an if-recognizable condition? This judgment is treated as a string constant with a value of true

Reply to discussion (solution)

if (eval ("Return $condition;")) {

$condition = "2<=2 && 2>=1 && (SNB = = = SNB | | SNB = = = Hfu) "; if (eval (" Return $condition; ")) {echo 1;} else {echo 2;}

Eval () can solve the case of pure numbers, the string has an English letter will be error, if it is above the situation what to do?

2<=2 && 2>=1 && (SNB = = SNB | | snb = = = Hfu)
itself is not a valid PHP conditional expression, do not say Eval, is that you write directly in if is to error.

        $condition = "2<=2 && 2>=1 && (SNB = = = SNB | | SNB = = = Hfu) "; if (eval (" Return $condition; ")) {echo 1;} else {echo 2;} if (2<=2 && 2>=1 && (' snb ' = = = ' SNB ' | | ' SNB ' = = = ' Hfu ') {echo 3;}

Well, the first paragraph of the $condition and the second paragraph if the content is equivalent it is just a string, one is the normal if condition.
There's no problem with running the second paragraph.
The first call to Eval () will report a constant undefined error, which should be escaped here?

        $condition = "2<=2 && 2>=1 && (SNB = = = SNB | | SNB = = = Hfu) "; if (eval (" Return $condition; ")) {echo 1;} else {echo 2;} if (2<=2 && 2>=1 && (' snb ' = = = ' SNB ' | | ' SNB ' = = = ' Hfu ') {echo 3;}

Well, the first paragraph of the $condition and the second paragraph if the content is equivalent it is just a string, one is the normal if condition.
There's no problem with running the second paragraph.
The first call to Eval () will report a constant undefined error, which should be escaped here?

Your intention is (' SNB ' = = = ' SNB ' | | ' SNB ' = = = ' Hfu ') but you write (SNB = = = SNB | | snb = = = Hfu) A variable that does not even have a $ symbol, is naturally understood as constant, yet you do not define a constant.

Convert them with variables, otherwise SNB and HFU will be interpreted as constants.

$SNB = "SNB"; $hfu = "Hfu";    $condition = ' 2<=2 && 2>=1 && ($snb = = = $SNB | | $snb = = = $hfu) ';    if (eval ("Return $condition;")) {        echo 1;    } else {        echo 2;    }

Uh, it's settled, thank you, big God.

Uh, it's settled, thank you, big God.

That's a knot.

