Question

Hey I have the following code which I’m using to isolate the a b c variables to use in the quadratic formula.

    $equation = '-5x^2–3x+4';
    $pattern = '/(?:^|[^\^])((?:\- *)?\d+)/';
    preg_match_all($pattern, $equation,  $pieces);
    if (substr($equation, 0) == 'x') 
    {
        $pieces_final[0][0] = 1;
        $pieces_final[0][1] = $pieces[0][0];
        $pieces_final[0][2] = $pieces[0][1];

    } 
    else 
    {
        $pieces_final = $pieces;
    }       
    print_r($pieces_final);

and it’s not working, it’s showing a weird ascii character in replace of the negative sign infront of the three, I really have no clue what could be wrong.

Answer 1

That’s not a negative sign.

>>> hex(ord(u'–'))
'0x2013'
>>> unicodedata.name(u'–')
'EN DASH'