PHP：将数组值拆分为键和值[关闭]

Question

I have a txt file which contains:

1:2
2:5
3:10
4:1

I need to be able to add to these numbers. For example I want to add to the last line +5:

1:2
2:5
3:10
4:6

How can I achieve this? I was wondering if the right way was to input the file into an array but I have no idea how to do this as I need to separate the numbers into keys and values, I guess?

Answer 1

The problem as described is pretty generic, but I can do some assumptions to help you.

The initial txt file is basically a key-value store:

1:2
2:5
3:10
4:1

Assuming that the first number is the key, you should tell your algorithm to perform a +x sum to the line with key n.

In (untested & not optimized) php code:

function addToStore($destKey, $numberToSum) {
    $newStore = [];

    foreach(file('store.txt') as $line) {
        list($key, $value) = explode(':', $line);

        if( $key === $destKey) {
            $value += $numberToSum;
        }

        newStore[] = "$key:$value";
    }

    file_put_contents('store.txt', implode("
", $newStore));
}

Then call it as:

addToStore('4', '5');