Should I create additional variables for better readability of the code?

Question

PHP

It is possible to write highly readable and self-documenting code, but sometimes this requires creating additional variables and breaking lines of code. How good or bad is this practice?
Simple example:

// $prices - двумерный массив с ценами
// $type - тип параметра
foreach($prices as $price) {
    $amount = $price[$type];
    $total += $amount;
}

Shorter version:

// $prices - двумерный массив с ценами
// $type - тип параметра
foreach($prices as $price) {
    $total += $price[$type];
}

Which style is preferred?

Answer 1

Depends on the situation. In your example, the second one. But, in the case of the code below - the first one.

foreach($houses as $house) {
    $current_floor = $house[$floor];
    $rooms_count = count($current_floor['flats']['1-room']); // например, только 1-комнатные

    $total_rooms += $rooms_count;

    /* вышенаписанное гораздо лучше, чем
    $total_rooms += count($house[$current_floor]['flats']['1-room']);
    */
}

In general, when you feel that your code is becoming unreadable, ugly, or simply unmaintainable, take appropriate action to correct the situation, including creating intermediate variables to visually separate the code.

Answer 2

I look at the following criteria to take out to a variable:
1) collection[key] is used more than once
2) key is too heavy (complicated) - then I take out the key (keeping the logic of point 1)

Answer 3

There are no universal rules here. Look at the code with a fresh eye and think, will the steps of the algorithm be obvious in a white view?
You can also rely on the proximity of the algorithm to natural language: "for each price tag, add a certain type of price tag to the total price tag." That is, the additional variable here rather adds verbosity - an extra entity that needs to be kept in mind.

Answer 4

2nd.
it is not only shorter, but also much less resource intensive.
Well, and ... "crowbar in the sleeve": php.net/manual/ru/function.array-sum.php

Answer 5

And it's easier like this:

$total = array_column($prices, $type);
$total = array_sum($total);

Answer 6

The most common problem...
I would choose the third way and call $type humanly, without creating an extra variable and explicitly making it clear that "type" is not some abstract substance, but a concrete thing, in this case the sum type.

<?php

foreach($prices as $price) {
    $total += $price[$amountType];
}