What I'm trying to achieve is a nested condition like if ((a = true && b = true) or (c = true && d = true)) {...}. This doesn't seem to be working for me.
To further explain: I have two variables in what we could call a 'top', and two variables in what we could call a 'bottom'. What I need to do is execute code if variables are true in both 'top' and 'bottom'.
To more succinctly illustrate:
if ((t1 = true && b1 = true) or
(t1 = true && b2 = true) or
(t2 = true && b1 = true) or
(t2 = true && b2 = true)
) {
...do some stuff...
}
I'm tempted to call it 'conditional statement for lattice problem'... except it isn't really a lattice problem... but it does sort of look like a lattice if you drew it |X| ... s'yeah, you're amazing if you can tell me a good way to do this, and you're super amazing if you can tell me what I ought to call it.
= is used for assignment, == is used to test for equality, === is used to test for equality and equal types. You need to use either == or ===, depending on whether t1, t2, b1, b2 are already boolean or something else. Also the stuff that Adam said, except that or is perfectly valid.
You need to use two equal signs == instead of =. Also, your variables need to have $ in front of them. And your "or" should be ||.
The logic is ok.
It should look like this:
if (($t1 == true && $b1 == true) ||
($t1 == true && $b2 == true) ||
($t2 == true && $b1 == true) ||
($t2 == true && $b2 == true)
) {
...do some stuff...
}
change condition
if (($t1 == true && $b1 == true) or
($t1 == true && $b2 == true) or
($t2 == true && $b1 == true) or
($t2 == true && $b2 == true)
)
= is assignment operator == is comparison operator.
Related
I have been making stuff in PHP for a while, everything is always fine. But today I don't get this statement. Why is it always true?
if ($action != 1 || $action != 2) echo true; // TRUE for 0, 1, 2, 3
But the reverse logic
if ($action == 1 || $action == 2) echo true; // FALSE for 0, 3 TRUE for 1, 2
The first expression blows my mind. I guess I don't understand something very very basic, not in PHP but in the Universe, so I don't get it here. I thought that if (FALSE || TRUE) == FALSE, but it isn't a case for second example. It works as expected.
So, where is the answer how to say that: "If the variable is not 1 OR 2 - echo true". I don't understand why my if ($var != 1 OR $var != 2) echo true; doesn't work as I expect.
Negation of ($action != 1 || $action != 2) is ($action == 1 && $action == 2). You can see for yourself that the latter is always false because variable can not be both 1 and 2 at the same time. Therefore the original condition is bound to be always true.
It is working as it has to work. See the doc http://php.net/manual/en/language.operators.logical.php
$a || $b returns TRUE if either $a or $b is TRUE.
If you try like this, hope it will make sense, see the comment on every line
$action = 0;
var_dump($action != 1 || $action != 2); //here (true || true)
$action = 1;
var_dump($action != 1 || $action != 2); //here (false || true)
$action = 2;
var_dump($action != 1 || $action != 2); //here (true || false)
$action = 3;
var_dump($action != 1 || $action != 2); //here (true || true)
Condition OR will search for first TRUE result, your code will give TRUE all the time as any value will be even not 1 or 2.
From you example if $action = 1 then the condition $action != 2 will give true, also if $action = 2 then $action != 1 will give TRUE.
For (If the variable is not 1 OR 2 - echo true) use this:
if(!in_array($action, array(1,2)) echo "true";
EDIT:
You can also check it like this:
if(!($action == 1 || $action == 2)) echo "true";
if ($action == 2 || $action == 1) echo true; // FALSE for 0, 3 TRUE for 1, 2
Works as intended. Its basically "echo true if $action is either 1 or 2".
I have this if statement but how can I add more conditions to it?:
if($row['Type']==$rtype){
}
I would like to have two conditions so when $row['Type']=A and $rtype=B and vise versa all others should be match exact but in case when Type A and B comes together I want to allow the statement display result.
I tried by adding:
($row['Type']=='A' && $rtype=='B') || ($row['Type']=='B' && $rtype=='A')
as:
if(...&& (($row['Type']==$rtype) || ($row['Type']=='A' && $rtype=='B') || ($row['Type']=='A' && $rtype=='B'))) {
}
What is the best way to approach this?
From your comment above, it sounds like you may need more clearly define when to "show" and when to "not show". Typically, if there are only two scenarios — either show or don't show — then you wouldn't need two if conditions.
However, with what you describe above, this should work:
if (($rtype == 'A' && $row['Type'] == 'B') || ($rtype == 'B' && $row['Type'] == 'A')) {
return true;
}
if (($rtype == 'D' && $row['Type'] == 'D') || ($rtype == 'E' && $row['Type'] == 'E') || ($rtype == 'F' && $row['Type'] == 'F') {
return false;
}
Note that each group is contained within its own ( and ). That does the AND you're looking for. Outside of each group, the || will do the OR.
If you know that you don't want to "show" if the first if doesn't evaluate to true, then you can simply do:
if (($rtype == 'A' && $row['Type'] == 'B') || ($rtype == 'B' && $row['Type'] == 'A')) {
return true;
}
return false;
I'm not sure what "show" and "don't show" mean so I'm just assuming a true/false will do for you.
Also check out the Operator Precedence link that abhishek posted above. That might give you some more general knowledge about how to group your logical expressions.
I have a problem with a form check that use an if statement with multiple 'and' and 'or' operators. This check return me an anomalous occasionally false value.
public function insert_checkForm($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
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
}