Question

I have a string like this: x+1=13-x

What I have to do, is separate the unknown (x) from mathematical symbols (+, -, *, : or /) and numbers. That means that the left side of the string would be an array like [x,+,1] and the right side: [13,-,x].

Before this, I was only working with one-digit numbers, so, I just used str_split() function, but, now I would like to use RegEx which I am not good at.

Answer 1

You’ll need to adapt this a bit, but try this:

<?php
$data = "a+123=x-23";
$arr = preg_split("/\\b/", $data);
print_r($arr);
?>

$ php t.php
Array
(
    [0] => 
    [1] => a
    [2] => +
    [3] => 123
    [4] => =
    [5] => x
    [6] => -
    [7] => 23
    [8] => 
)

As you can see, the individual components are visible in the resulting array. You’ll need to take care of whitespace issues.