如何在不递增的情况下按字母顺序获取下一个字母？ （PHP）

Question

for ($i=A;$i<L;$i++){                   
    echo $i;
    echo '->';
    echo ++$i;
    echo ', ';
}

gives me:

A->B, C->D, E->F, G->H, I->J, K->L

what I want is:

A->B, B->C, C->D, D->E, E->F, F->G

What's the simplest way to do this?

Answer 1

How about just copying the value before incrementing it:

for ($i = 'A'; $i < 'L'; $i++) {                   
    $j = $i;
    $j++;
    echo "$i->$j, ";
}

Ps. You really should quote your string constants. Otherwise your logs will be full of warnings like these:

PHP Notice:  Use of undefined constant A - assumed 'A' in - on line 2
PHP Notice:  Use of undefined constant L - assumed 'L' in - on line 2