Change if condition dynamically - php

Question

I'd like to dynamically change a condition, depending on whether or not a table is empty.
If the table is empty, it should record all data up to yesterday, if not empty, it should record today's data.
My current code is not working:
$db->get('history');
$emptyTable = $db->count; // This return 0 or 1
$condition = setCondition($emptyTable);
foreach($extract as $trade) {
$date = strtotime($trade['Date']);
$today = strtotime(date("d/m/Y"));
if($condition) {
// do something
}
}
function setCondition($bool) {
switch ($bool) {
case 1:
return $date == $today;
break;
case 0:
return $date < $today;
break;
}
}

Answer 1

You are not passing $date and $today to your function and call it inside foreach and enclose the return part in setCondition so that it will return the string ..
foreach($extract as $trade) {
$date = strtotime($trade['Date']);
$today = strtotime(date("d/m/Y"));
$condition = setCondition($emptyTable,$today,$date);
// echo $condition//condition string
if($condition) {
// do something
}
}
function setCondition($bool,$today,$date) {
switch ($bool) {
case 1:
return "'$date' == '$today'";
break;
case 0:
return "'$date' < '$today'";
break;
}
}
DEMO

Answer 2

Your condition itself needs to be a call to a function returning a boolean value. This is what your setCondition function does:
function setCondition($bool) {
switch ($bool) {
case 1:
return $date == $today;
break;
case 0:
return $date < $today;
break;
}
}
Since it does not set anything, I suggest you rename it evaluateCondition.
Henceforth, you can directly call this function as a condition:
if(evaluateCondition($booleanVariableToTest)) {
// do something
}
Regarding why your code does not work: you basically evaluate $condition once, at the beginning:
$condition = setCondition($emptyTable);
After that, $condition never changes. Therefore, it is not dynamically re-evaluated.
Edit
From reading a comment of you, I understand that you're not actually trying to dynamically evaluate a condition, but statically evaluate it, depending on other parameters (namely, $date and $today).
Your function needs to take these variables as arguments, so their names actually mean something in the scope of this function. The right code is:
function setCondition($bool, $date, $today) {
switch ($bool) {
case 1:
return $date == $today;
break;
case 0:
return $date < $today;
break;
}
}
In this case, you do not need to call the setCondition function at every iteration, so your if test remains:
if($condition) {
// do something
}