Condensing PHP code into functions

Question

I have a repeating code in php that I would imagine I can somehow condense into a function and simply call the function multiple times. I tried doing this and nothing appears to happen. This is on repetition of the old code:

if ($health_1 > $health_2) {
    $health_left = '#7fba00';
    $health_right = '#e81123';
} else if ($health_perlvl_1 == $health_perlvl_2) {
    $health_left = '#0451ff';
    $health_right = '#0451ff';
} else {
    $health_left = '#e81123';
    $health_right = '#7fba00';
}

and this repeats about 12 times with other stats. I decided to try to condense it to this:

function stat_color($stat_1,$stat_2,$color_left,$color_right) {
    if ($stat_1 > $stat_2) {
        $color_left = '#7fba00';
        $color_right = '#e81123';
    } else if ($stat_1 == $stat_2) {
        $color_left = '#0451ff';
        $color_right = '#0451ff';
    } else {
        $color_left = '#e81123';
        $color_right = '#7fba00';
    }   

}
stat_color($health_1,$health_2,$health_left,$health_right);

But the colors are not there later when they are needed. Is there any way to actually get this to work?

Your functions are useless unless they actually DO something. Right now they're just setting local variables that are destroyed when the function returns. perhaps you want return(array('left' => '#7fba00', 'right' => '#e81123')); or similar. — Marc B
– Marc B, Commented Feb 28, 2014 at 20:32
@MarcB You could write the answer in the answer box too, just sayin — Jack M.
– Jack M., Commented Feb 28, 2014 at 20:33
@MarcB I had return $color_left; and return $color_right; at the end and that did nothing. I'm not really sure how that array works — user1895377
– user1895377, Commented Feb 28, 2014 at 20:34
you can only return a single value from a function call. once you return, the function's dead and gone. hence the array - put whatever multiple values you want to return into that array and return the array. — Marc B
– Marc B, Commented Feb 28, 2014 at 20:54

Rob · Accepted Answer · 2014-02-28 20:36:50Z

2

Try this:

function stat_color($stat_1,$stat_2,&$color_left,&$color_right) {

That way it will update the variables you pass into the function.

answered Feb 28, 2014 at 20:36

Rob

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2 Comments

ficuscr Over a year ago

Understanding byref / byval relates to this question but I do not approve of this as a solution. I would rather see a function that 'returns' something.

halfer Over a year ago

+1 because it will work, though I agree with @ficuscr - pass-by-ref can be considered a side-effect.

2 revs, 2 users 91% · Accepted Answer · 2014-02-28 20:47:10Z

1

Of course, since formal parameters are local to function scope their values cannot be used outside function. Try this.

Since we cannot return multiple values, I have used an array with appropriate keys.

function stat_color($stat_1,$stat_2) {

    $arr = array(); 
    if ($stat_1 > $stat_2) {
        $arr["color_left"] = '#7fba00';
        $arr["color_right"] = '#e81123';
    } else if ($stat_1 == $stat_2) {
        $arr["color_left"] = '#0451ff';
        $arr["color_right"] = '#0451ff';
    } else {
        $arr["color_left"] = '#e81123';
        $arr["color_right"] = '#7fba00';
    }   

    return arr;
}

You can now use:

$colors = stat_color(stat1,stat2);

Use $colors["color_left"] or $colors["color_right"] to refer to appropriate colors.

edited Feb 28, 2014 at 20:47

community wiki

2 revs, 2 users 91%
udit

4 Comments

CodeAngry Over a year ago

remove the color_ in $arr. They bloat the code. 'left' and 'right' and meaningful enough for a function named stat_color.

halfer Over a year ago

@udit: so you know, if you make an answer "community wiki", you don't get the reputation points. CW is useful if you are writing an answer on behalf of the OP, and wish to forego the rep points.

Udit Narayan Over a year ago

I did not know that. But I thought it might be helpful for me to make my answers wiki as other people can edit it if they feel something is wrong or can be improved, as I have just started to answer questions on this site. Thanks for information @halfer

halfer Over a year ago

People can edit your answers regardless of whether they are CW. If they have below a certain rep threshold (2,000 I think) their edits go into an approval queue; above this they are approved automatically.

halfer · Accepted Answer · 2014-02-28 20:42:46Z

0

You could return the strings thus:

return array('#7fba00', '#e81123');

And then when you want to get them again:

list($health_left, $health_right) = stat_color($health_1, $health_2);

You can do this with pass-by-reference variables, but it feels less elegant.

answered Feb 28, 2014 at 20:42

halfer

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