I have a problem with a form check that use an if statement with multiple 'and' and 'or' operators. This check return me an anomalous occasionally false value.
public function insert_checkForm($form) {
$form = array_filter($form);
if (
!isset($form['report_id']) ||
!isset($form['date']) ||
!isset($form['technical_id']) ||
isset($form['travel_go_from']) != isset($form['travel_go_to']) ||
isset($form['work_go_from']) != isset($form['work_go_to']) ||
!isset($form['travel_go_from']) &&
!isset($form['travel_go_to']) &&
!isset($form['work_go_from']) &&
!isset($form['work_go_to'])
) {
return false;
} else {
return $form;
}
}
Last question, the above code changes compared to this (in spite of the priorities of and operators)?
[...]
!isset($form['report_id']) ||
!isset($form['date']) ||
!isset($form['technical_id']) ||
(isset($form['travel_go_from']) != isset($form['travel_go_to'])) ||
(isset($form['work_go_from']) != isset($form['work_go_to'])) ||
(!isset($form['travel_go_from']) && !isset($form['travel_go_to']) && !isset($form['work_go_from']) && !isset($form['work_go_to']))
[...]
Thanks =)
The most common problem with isset() is that it returns false when the item is NOT SET but also returns false if the item IS SET && IS NULL.
isset($arr['nonexisting']); //this returns: false
$arr['existing'] = null;
isset($arr['existing']); //this returns: false
Related
This question already has answers here:
Why does non-equality check of one variable against many values always return true?
(3 answers)
Closed 6 years ago.
The first one with equals will work and I would expect that. But the second is not working as expected.
$nicktest = "new";
if ($nicktest == "new" || $nicktest == "fun" || $nicktest == "norm" || $nicktest == "pvp")
{
$odpoved = "Ok it works.";
echo $odpoved;
return;
}
$nicktest = "new";
if ($nicktest != "new" || $nicktest != "fun" || $nicktest != "norm" || $nicktest != "pvp")
{
$odpoved = "Ok it works too why?";
echo $odpoved;
return;
}
Your 4 conditions get the following evaluation:
false, true, true, true
Now,
if (false || true || true || true) {
// Code block is actually evaluated
}
If you would happen to have:
if (false || false || false || false) {
// Code block wouldn't be evaluated
}
Under this scheme, at least one true condition would get the code to be evaluated
I'm sorry for the vaguely described title. This is what I want:
if($a[$f] === false || $a[$g] === false || $a[$h] === false || $a[$i] === false || $a[$j] === false)
{
// do something
}
I want to do something with the condition that actually triggered the statement (if a[$f] = true and a[$g] = false, I want to do something with $g).
I know that in this case, the first statement that went true (i.e. $a[$g] == false) triggers. But is there any way to do something with $g? I've never seen this in my programming life before and can't seem to find anything about it.
Thanks in advance.
--- Edit ---
I forgot to mention: I'm using a function on all the array data. So, shortened, I get this:
if(valid($a[$f]) === false || valid($a[$g]) === false)
{
// do something
}
--- Edit 2 ---
This piece of OOP-based PHP, where I'm in a class, is my code.
if($this->validatedText($product[$iName]) == false ||
$this->validatedUrl($product[$iUrl]) == false ||
$this->validatedNumber($product[$iTax]) == false ||
$this->validatedValuta($product[$iPrice]) == false ||
$this->validatedText($product[$iArticleNumber]) == false ||
$this->validatedText($product[$iDescription]) == false ||
$this->validatedText($product[$iMetaDescription]) == false ||
$this->validatedText($product[$iTitle]) == false)
{
// do something with the first iVariable
}
Simplest solution will be
if(false!==($sIndex = array_search(false, $a, 1)))
{
//your $sIndex is first index with false value
}
if you want all keys, you may use array_filter(), like this:
$rgFalse = array_keys(array_filter($a, function($x)
{
//here valid is your function
return false===valid($x);
}));
I can’t get the desired result from a series of conditions in an IF.
if (($varteam == $_POST['rteam1']) && ($varteam == $_POST['rteam2']) && ($varteam == $_POST['rteam3']) && ($varteam == $_POST['rteam4']) && ($varteam == $_POST['rteam5']))
{true}
else
{false}
Starting from the variable $varteam I want to obtain true if all the compared values are identical, otherwise false.
The compared values may also be null.
With the code I’ve posted it works if all the values are equal or different but I get true instead of false if one or more values are different.
Why does it happen?
I am guessing that you may get false positives when you have 0 mixed with null or false. Just to be on the safe side, use === instead of == so type checking is in effect. That way, null !== false !== 0.
if (($varteam === $_POST['rteam1']) &&
($varteam === $_POST['rteam2']) &&
($varteam === $_POST['rteam3']) &&
($varteam === $_POST['rteam4']) &&
($varteam === $_POST['rteam5']))
{
// true
}
else
{
// false
}
Why this condition passes even if I change the $_GET variable?
I've this code
elseif(isset($_GET['results']) && $_GET['results'] == 'reorder' &&
isset($_GET['sort_column']) && $_GET['sort_column'] != '' && isset($_GET['sort_order'])
&& $_GET['sort_order'] != '' && $_GET['sort_order'] == 'asc'
|| $_GET['sort_order'] == 'desc') { /*rest goes here*/ } else {redirect}
Link returns like this
http://localhost/system/results.php?script_id=2&results=reorder&sort_column=supplier_address&sort_order=desc
But when I change this sort_column=supplier_address to say for example sorcodsalumn=supplier_address it doesn't redirect, instead goes ahead, any idea why? But if I simply remove few letters and dont replace with something else it does redirect...
How come if am using this isset($_GET['sort_column'] and am modifying sort_column to something else still passes this condition
Basic PHP operator precedence... && evaluates before ||, so your entire statement boils down to:
(x && y && z && ....) || ($_GET['sort_order'] == 'desc')
You need to simplify that if(), add some () to enforce your own evaluation order, and then things should start working a bit better.
your AND's and OR's need to be bracketed properly.
else if (isset($_GET['results']) &&
$_GET['results'] == 'reorder' &&
isset($_GET['sort_column']) &&
$_GET['sort_column'] != '' &&
isset($_GET['sort_order']) &&
$_GET['sort_order'] != '' &&
($_GET['sort_order'] == 'asc' || $_GET['sort_order'] == 'desc'))
{
/*rest goes here*/
} else {
redirect
}
More specifically your last || needs its own brackets, as shown above.
You need to put a bracket around your || (OR) statement like this:
elseif(isset($_GET['results']) && $_GET['results'] == 'reorder' &&
isset($_GET['sort_column']) && $_GET['sort_column'] != '' && isset($_GET['sort_order'])
&& $_GET['sort_order'] != '' && ($_GET['sort_order'] == 'asc'
|| $_GET['sort_order'] == 'desc')) { /*rest goes here*/ } else {redirect}
Otherwise your statement will return true anytime sort_order is set to 'desc'.
This may be the way my server is set up, but I'm banging my head against the wall. I'm trying to say that if $action has no value or has a value that is not "add" or "delete" then have an error, else keep running the script. However, I get an error no matter what $action is.
$action = $_GET['a'];
if((!isset($action)) || ($action != "add" || $action != "delete")){
//header("location:index.php");
echo "error <br>";
}
$action is being set properly and if run something like if($action =="add") it works. This is on my local host, so it could be a settings issue.
Your logic is slightly off. The second || should be &&:
if ((!isset($action)) || ($action != "add" && $action != "delete"))
You can see why your original line fails by trying out a sample value. Let's say $action is "delete". Here's how the condition reduces down step by step:
// $action == "delete"
if ((!isset($action)) || ($action != "add" || $action != "delete"))
if ((!true) || ($action != "add" || $action != "delete"))
if (false || ($action != "add" || $action != "delete"))
if ($action != "add" || $action != "delete")
if (true || $action != "delete")
if (true || false)
if (true)
Oops! The condition just succeeded and printed "error", but it was supposed to fail. In fact, if you think about it, no matter what the value of $action is, one of the two != tests will return true. Switch the || to && and then the second to last line becomes if (true && false), which properly reduces to if (false).
There is a way to use || and have the test work, by the way. You have to negate everything else using De Morgan's law, i.e.:
if ((!isset($action)) || !($action == "add" || $action == "delete"))
You can read that in English as "if action is not (either add or remove), then".
No matter what $action is, it will always either not be "add" OR not be "delete", which is why the if condition always passes. What you want is to use && instead of ||:
(!isset($action)) || ($action !="add" && $action !="delete"))
You're saying "if it's not set or it's different from add or it's different from delete". You realize that a != x && a != y, with x != y is necessarily false since a cannot be simultaneously two different values.
You could also try:
if ((!isset($action)) || !($action == "add" || $action == "delete")) {
// Do your stuff
}
For future reference, you can quickly create a truth table to check if it evaluates the way you want... it's kind of like Sudoku.
(!isset($action)) && ($action != "add" && $action != "delete"))
Example:
column 1 is issetaction, column 2 and 3 evaluates !="add","delete" respectively
if($a=add) T && (F && T) => T && F => FALSE
if($a=delete) T && (T && F) => T && F => FALSE
if($a=nothing) T && (T && T) => T && T => TRUE
I think this is the best and easiest way to do it:
if (!(isset($action) && ($action == "add" || $action == "delete")))
Not an answer, but just for the sake of code formatting
if((isset($_GET['a'])) $action=$_GET['a']; else $action ="";
if(!($action === "add" OR $action === "delete")){
header("location: /index.php");
exit;
}
Note the exit; statement after header(). That's the important thing. header() does not terminate script execution.