字符串混淆1）或者如果是cond。 并且strtolower不降低

Question

Trying to convert times such as - 215pm or 2:15 am or whatever to a 14:15 or 02:15 type string. (I am NOT using a TIME format for reasons to tedious to go into.)

Have managed to get an array output that contains hours, minutes and am/pm (but only if characters are present).

I want to allow erroneous characters through so I can EXPLICITLY fire an error message but a) I cannot get a "simple" OR test to work and b) strtolower is not working for me - I don't know why.

$hour= $matches['h'];
$minute=$matches['m'];

if(!array_key_exists('ap', $matches)){$matches ['ap'] ="am";};
$ampm=$matches['ap'];
strtolower ($ampm);

  debug ($hour,"hr");
  debug ($minute,"min");
  debug ($ampm,"ampm");

if ($ampm=="am" or $ampm=="pm") {echo "fine";}; // ALWAYS TRUE

if ($ampm==="am" or $ampm==="pm") {echo "fine";}; // FAILS WITH UPPER CASE AM AND PM

if ($hour<12 and $ampm=="pm") {$hour = $hour+12;};
  debug ($hour,"hr");
  debug ($minute,"min");
  debug ($ampm,"ampm");

So I do not understand why the simple string test $ampm=="am" or $ampm=="pm" is always true but that is just academic. But I REALLY do not understand why strtolower does not change "AM" to "am" so that I cannot even use a === congruence test.

Any thoughts?

Answer 1

Do this to replace the variable:

$ampm = strtolower($ampm);

Also, $ampm is always true because the condition says

"if it is am, it is true OR if it is pm, it is true"

so what you want to do is:

if(isset($ampm) && $ampm === "am")
{
    //its am
} else if(isset($ampm) && $ampm === "pm")
{
    //its pm
} else
{
    //its neither
}