PHP string operation for negative judgment analysis _php tips

This article analyzes the method of judging the negative value of PHP string operation. Share to everyone for your reference, specific as follows:

$a = '-1 ';
$b = (int) $a;
$c = Is_numeric ($a);
if ($a) {
 echo 1;//echo 1
} else {
 echo 2;
}
Var_dump ($b); Int ( -1)
var_dump ($c);//True

The output of the run results is as follows:

1
Int-1
Boolean true

Summarize:

The logical value of the string '-1 ' is true;

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