I have a var which return TRUE or FALSE. how do I use ternary logic to return the string
"YES" if $var1 is TRUE and
"NO" if $var1 is FALSE ?
$Var1 = TRUE; /*dynamic value*/
$status = ($Var1 == true ? $Var1:"NO");
Thank you.
$status = $Var1 ? 'YES' : 'NO';
You cannot go shorter than that :)
you do not need neither () nor == TRUE since if $var1 returns true if it is not null, 0 or false.
$status = ($Var1 == true ? "YES":"NO");
$status = ( $var1 === true ) ? "YES" : "NO";
Related
I need to display true or false not the number 1
$permission === 1 ? true: false
nearly right:
$permission= ($permission === 1) ? 'true': 'false';
echo $permission;
http://php.net/manual/en/language.operators.comparison.php
First you dont make any assignment =
then you have to make a comparison $permission === 1
then you want the string values "true" or "false"
change the boolean to string value
$permission === 1 ? 'true': 'false';
Its as simple as
echo "Output : ".($permission == 1) ? 'true': 'false';
This question already has answers here:
Reference Guide: What does this symbol mean in PHP? (PHP Syntax)
(24 answers)
Closed 9 years ago.
if ($form->isValid()) {
// ... perform some action, such as saving the task to the database
$nextAction = $form->get('saveAndAdd')->isClicked()
? 'task_new'
: 'task_success';
return $this->redirect($this->generateUrl($nextAction));
}
Here is the link to the documentation
http://symfony.com/doc/current/book/forms.html
The class documentation says that it returns a bool.
What is the point of
? 'task_new'
: 'task_sucess';
That is called "ternary" and it's awesome:
This is assigning the value $nextAction based on a condition. The first part (after the =) is the condition, like an if statement, the second part (after the ?) is the value assigned if the condition is true, and the last part (after the :) is the value assigned if the condition is false.
//the condition
$nextAction = $form->get('saveAndAdd')->isClicked()
? 'task_new' //true value
: 'task_success'; //false value
It is a shorter way of writing this:
if ($form->get('saveAndAdd')->isClicked()) {
$nextAction = 'task_new';
}
else {
$nextAction = 'task_success';
}
So, here's some easy examples:
$foo = (true) ? 'True value!' : 'False value!';
echo $foo; //'True value!' of course!
$foo = (false) ? 'True value!' : 'False value!';
echo $foo; //'False value!' of course!
It's the Ternary operator. The syntax is as follows:
value = (condition) ? run if true : run if false;
In this case, if $form->get('saveAndAdd')->isClicked() is true, then task_new. Else task_success.
If could be rewritten like so:
if($form->get('saveAndAdd')->isClicked()) {
$value = "task_new";
} else {
$value = "task_success";
}
The ternary operator is a shorter form for an if statement.
The : is the "else" part.
Example in Java:
boolean bool;
true ? bool = true : bool = false;
It's a senseless example, but shows the ternary operator very well.
if the condition, here true is "true", then fill into the variable bool true, else false.
alternative if-statement in Java to the code example above:
boolean bool;
if(true)
bool = true;
else
bool = false;
This is a Ternary Operator which is a short hand if else statement. This is equivalent to
if($form->get('saveAndAdd')->isClicked()){
$nextAction = 'task_new'
else{
$nextAction = 'tassk_success'
}
This is the ternary opeator, a short-hand expression that works the same as an if
$value = someFunc() ? "whatever" : "the other"
is equivalent to
if (someFunc()) {
$value = "whatever";
} else {
$value = "the other";
}
This is equivalent to "if" and "else" statements.
This code :
$nextAction = $form->get('saveAndAdd')->isClicked()
? 'task_new'
: 'task_success';
is equivalent to this code :
if ( $form->get('saveAndAdd')->isClicked() )
{
$nextAction = 'task_new';
}
else
{
$nextAction = 'task_success';
}
Is there a function to check both
if (isset($var) && $var) ?
The empty() function will do the job.
Use it with the not operator (!) to test "if not empty", i.e.
if(!empty($var)){
}
You may use the ?? operator as such:
if($var ?? false){
...
}
What this does is checks if $var is set and keep it's value. If not, the expression evaluates as the second parameter, in this case false but could be use in other ways like:
// $a is not set
$b = 16;
echo $a ?? 2; // outputs 2
echo $a ?? $b ?? 7; // outputs 16
More info here:
https://lornajane.net/posts/2015/new-in-php-7-null-coalesce-operator
there you go. that should do it.
if (isset($var) && $var)
if (! empty($var))
It seems as though #phihag and #steveo225 are correct.
Determine whether a variable is considered to be empty. A variable is
considered empty if it does not exist or if its value equals FALSE.
empty() does not generate a warning if the variable does not exist.
No warning is generated if the variable does not exist. That means
empty() is essentially the concise equivalent to !isset($var) || $var
== false.
So, it seems !empty($var) would be the equivalent to isset() && $var == true.
http://us2.php.net/empty
Try the empty function:
http://us2.php.net/empty
isset($a{0})
isset AND len is not 0 seems more reliable to me, if you run the following:
<?php
$a=$_REQUEST['a'];
if (isset($a{0})) { // Returns "It's 0!!" when test.php?a=0
//if (!empty($a)) { // Returns "It's empty!!" when test.php?a=0
echo 'It\'s '.$a;
} else { echo 'It\'s empty'; }
?>
$a = new stdClass;
$a->var_false = false;
$a->var_true = true;
if ($a->notSetVar ?? false) {
echo 'not_set';
}
if ($a->var_true ?? false) {
echo 'var_true';
}
if ($a->var_false ?? false) {
echo 'var_false';
}
This way:
if (($var ?? false) == true) {
}
I am amazed at all these answers. The correct answer is simply 'no, there is no single function for this'.
empty() tests for unset or false. So when you use !empty(), you test for NOT UNSET (set) and NOT FALSE. However, 'not false' is not the same as true. For example, the string 'carrots' is not false:
$var = 'carrots'; if (!empty($var)){print 1;} //prints 1
in fact your current solution also has this type problem
$var = 'carrots'; if (isset($var) && $var){print 1;} //prints 1
as does even this
$var = '1.03'; if (isset($var) && $var == true){print 1;} //prints 1
in fact... if you want to do as you described exactly, you need:
$var = 'carrots'; if (isset($var) && $var === true){print 1;} //Note the 3 Equals //doesn't print 1
I suppose the shortest valid way to test this case is :
if (#$var === true){ print 1;}
But suppressing errors for something like this is pretty awful practice.
Don't know if an exact one already exists, but you could easily write a custom function to handle this.
function isset_and_true($var) {
return (isset($var) && $var == true) ? true : false;
}
if (isset_and_true($a)) {
print "It's set!";
}
Check if the variable is set, and true. Ignore warning message
if(#!empty($foo))
Is there a better way besides isset() or empty() to test for an empty variable?
It depends upon the context.
isset() will ONLY return true when the value of the variable is not NULL (and thereby the variable is at least defined).
empty() will return true when the value of the variable is deemed to be an "empty" value, typically this means 0, "0", NULL, FALSE, array() (an empty array) and "" (an empty string), anything else is not empty.
Some examples
FALSE == isset($foo);
TRUE == empty($foo);
$foo = NULL;
FALSE == isset($foo);
TRUE == empty($foo);
$foo = 0;
TRUE == isset($foo);
TRUE == empty($foo);
$foo = 1;
TRUE == isset($foo);
FALSE == empty($foo);
Keep an eye out for some of the strange == results you get with PHP though; you may need to use === to get the result you expect, e.g.
if (0 == '') {
echo "weird, huh?\n";
}
if (0 === '') {
echo "weird, huh?\n";
} else {
echo "that makes more sense\n";
}
Because 0 is false, and an empty string is false, 0 == '' is the same as FALSE == FALSE, which is true. Using === forces PHP to check types as well.
I am trying to set a flag to show or hide a page element, but it always displays even when the expression is false.
$canMerge = ($condition1 && $condition2) ? 'true' : 'false';
...
<?php if ($canMerge) { ?>Stuff<?php } ?>
What's up?
This is broken because 'false' as a string will evaluate to true as a boolean.
However, this is an unneeded ternary expression, because the resulting values are simple true and false. This would be equivalent:
$canMerge = ($condition1 && $condition2);
The value of 'false' is true. You need to remove the quotes:
$canMerge = ($condition1 && $condition2) ? true : false;
Seems to me a reasonable question especially because of the discrepancy in the way PHP works.
For instance, the following code will output 'its false'
$a = '0';
if($a)
{
echo 'its true';
}
else
{
echo 'its false';
}
You are using 'true' and 'false' as string. Using a string(non-empty and not '0' and not ' ', because these are empty strings and will be assume as false) as a condition will results the condition to be true.
I will write some correct conditions that could be use:
$canMerge = ($condition1 && $condition2);
$canMerge = ($condition1 && $condition2) ? true : false;
$canMerge = ($condition1 && $condition2) ? 'true' : 'false';
...
<?php if ($canMerge == 'true') { ?>Stuff<?php } ?>
$canMerge = ($condition1 && $condition2);
then
if ($canMerge){
echo "Stuff";
}