CODEWITHSUNDEEP
phparrays
Sobia Safdar
Sobia Safdar

Reputation: 83

Perform mathematical calculation on dynamic array

I have a dynamic array.
Lets suppose 

array (size=3)  
  0 => string '20' (length=2)  
  1 => string '-' (length=1)  
  2 => string '5' (length=1)

its result will be 20-5 = 5

Array size is not defined , how can i solve it dynamically ?

Upvotes: 0

Views: 170

Answers (2)

Oleg Liski
Oleg Liski

Reputation: 583

You can use following code. Of course, it have some limitations. Depends on what you want to do and why you are doing it.

<?php

$array = array(
    '20',
    '-',
    '5',
    '*',
    '10'
);

$output = null;
$symbol = null;
foreach ($array as $item) {
    if ($item == '+' || $item == '-' || $item == '*' || $item == '/') {
        if ($output === null) {
            die("First item should be numeric! ");
        }
        $symbol = $item;
        continue;
    } elseif (!is_numeric($item)) {
        die("unknown symbol: " . $item);
    }

    // is numeric
    // first symbol

    if ($output == null) {
        $output = $item;
        continue;
    }

    if ($symbol === null) {
        die('Two numbers in a row!!');
    }

    switch ($symbol) {
        case '+':
            $output += $item;
            break;
        case '-':
            $output -= $item;
            break;
        case '*':
            $output *= $item;
            break;
        case '/':
            $output /= $item;
            break;

    }
}

echo "Calculation is: " . $output;

Upvotes: 2

maxhb
maxhb

Reputation: 8855

One of the few cases where phps most hated and feared function comes in handy.

The evil eval():

$input = array('20', '-', '5');

// build formula from array by glueing values together
$formula = implode(' ', $input);

// execute the formula and store result in $result
eval('$result  = ' . $formula . ';');

// voila!
echo $formula . ' = ' . $result;

The nice thing about using eval() is that you can use all mathematical operations known in php and even handling of brackets is fully supported.

Visit http://sandbox.onlinephpfunctions.com/code/71ffc94238a5510cd7b24632fc7a8b9b5cb2c2c0 for a working example with more formulas defined for testing.

Upvotes: 1

Related Questions