Arithmetic operations between variables
I start with php
. I am trying to apply some random arithmetic operation between two variables
$operators = array(
"+",
"-",
"*",
"/"
);
$num1 = 10;
$num2 = 5;
$result = $num1 . $operators[array_rand($operators)] . $num2;
echo $result;
it prints values like these
10+5 10-5
How can I change my code to do this arithmetic operation?
+3
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2 answers
While you can use it eval()
for this, it relies on safe variables.
This is much safer:
function compute($num1, $operator, $num2) {
switch($operator) {
case "+": return $num1 + $num2;
case "-": return $num1 - $num2;
case "*": return $num1 * $num2;
case "/": return $num1 / $num2;
// you can define more operators here, and they don't
// have to keep to PHP syntax. For instance:
case "^": return pow($num1, $num2);
// and handle errors:
default: throw new UnexpectedValueException("Invalid operator");
}
}
Now you can call:
echo compute($num1, $operators[array_rand($operators)], $num2);
+5
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This should work for you!
You can use this function:
function calculate_string( $mathString ) {
$mathString = trim($mathString); // trim white spaces
$mathString = preg_replace ('[^0-9\+-\*\/\(\) ]', '', $mathString); // remove any non-numbers chars; exception for math operators
$compute = create_function("", "return (" . $mathString . ");" );
return 0 + $compute();
}
//As an example
echo calculate_string("10+5");
Output:
15
So, in your case, you can do this:
$operators = array(
"+",
"-",
"*",
"/"
);
$num1 = 10;
$num2 = 5;
echo calculate_string($num1 . $operators[array_rand($operators)] . $num2);
0
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