I'd like to to some thing similar to JavaScript's
var foo = true;
foo && doSometing();
but this doesn't seem to work in PHP.
I'm trying to add a class to a label if a condition is met and I'd prefer to keep the embedded PHP down to a minimum for the sake of readability.
So far I've got:
<?php $redText='redtext ';?>
<label class="<?php if ($requestVars->_name=='')echo $redText;?>labellong">_name*</label>
<input name="_name" value="<?php echo $requestVars->_name; ?>"/>
but even then the IDE is complaining that I have an if statement without braces.
use the ternary operator ?:
change this
<?php if ($requestVars->_name == '') echo $redText; ?>
with
<?php echo ($requestVars->_name == '') ? $redText : ''; ?>
In short
// (Condition)?(thing's to do if condition true):(thing's to do if condition false);
You can use Ternary operator logic
Ternary operator logic is the process of using "(condition)? (true return value) : (false return value)" statements to shorten your if/else structures. i.e
/* most basic usage */
$var = 5;
$var_is_greater_than_two = ($var > 2 ? true : false); // returns true
Something like this?
($var > 2 ? echo "greater" : echo "smaller")
I like to use the minimalist PHP text output syntax:
HTML stuff <?= $some_string ?> HTML stuff
(This works the same as using an <?php echo $some_string; ?>)
You can also use the ternary operator:
//(condition) ? (do_something_when_true) : (do_something_when_false);
($my_var == true) ? "It's true" : "It's false ;
Ending up like this:
<?= ($requestVars->_name=='') ? $redText : '' ?>
Sample Usage
Here are a couple more uses of ternary operators, ranging from simple to advanced:
Basic Usage:
$message = 'Hello '.($user->is_logged_in() ? $user->get('first_name') : 'Guest');
Short hand Usage:
$message = 'Hello '.($user->get('first_name') ?: 'Guest');
Echo Inline
echo 'Based on your score, you are a ',($score > 10 ? 'genius' : 'nobody');
A bit Tougher
$score = 10;
$age = 20;
echo 'Taking into account your age and score, you are: ',($age > 10 ? ($score < 80 ? 'behind' : 'above average') : ($score < 50 ? 'behind' : 'above average')); // returns 'You are behind'
complicated level
$days = ($month == 2 ? ($year % 4 ? 28 : ($year % 100 ? 29 : ($year %400 ? 28 : 29))) : (($month - 1) % 7 % 2 ? 30 : 31)); //returns days in the given month
To learn more about ternary operators and usage, visit PHP.net Comparison Operators or here.
Use ternary operator:
echo (($test == '') ? $redText : '');
echo $test == '' ? $redText : ''; //removed parenthesis
But in this case you can't use shorter reversed version because it will return bool(true) in first condition.
echo (($test != '') ?: $redText); //this will not work properly for this case
Ill provide with an other answer since the original question specifies the use of if() in html
<a class="menu-item" href="/about-us"><?= (pll_current_language() == 'en') ? 'About us' : 'Om oss' ?></a>
The provided answers are the best solution in your case, and they are what I do as well, but if your text is printed by a function or class method you could do the same as in Javascript as well
function hello(){
echo 'HELLO';
}
$print = true;
$print && hello();
Related
I am new to PHP and I am struggling to see why my code is not working when the echo displays 0. The code works for everything else however whenever the random operator chooses 0 it outputs 0 Negative, when I have it to display as Zero. I have no idea why it is doing this and I would appreciate any guidance.
$randomNumber = rand(-5, 5);
$var = $randomNumber;
echo $randomNumber;
echo $integerValue = (($var === 0) ? " Zero" : ($var <=-1) ? " Negative" : (($var >=1) ? " Positive" : " Not Positive or Zero") );
The problem is due to PHP ternary operator precedence, which works backwards compared to most other languages:
Understanding nested PHP ternary operator
Try this last line:
echo $integerValue = (($var === 0) ? " Zero" : (($var <=-1)
? " Negative" : (($var >=1)
? " Positive" : " Not Positive or Zero") ));
You are missing a parentheses:
<?php
$randomNumber = rand(-5, 5);
$var = $randomNumber;
echo $randomNumber;
echo $integerValue = (($var === 0) ? " Zero" : (($var <=-1) ? " Negative" : (($var >=1) ? " Positive" : " Not Positive or Zero") ) );
Explanation:
(
($var === 0) ? " Zero" : (
($var <=-1) ? " Negative" : (
($var >=1) ? " Positive" : " Not Positive or Zero"
)
)
)
You don't want to echo the assignment. You need to assign the value, then echo it. Try changing the last line to
$integerValue = (($var === 0) ? " Zero" : ($var <=-1) ? " Negative" : (($var >=1) ? " Positive" : " Not Positive or Zero") );
and then adding the line
echo $integerValue;
You already have another answer that explains why you weren't getting the outcome you expected, but just FYI, your multiple ternary expression can be simplified somewhat.
echo $var ? $var > 0 ? ' Positive' : ' Negative' : ' Zero';
$var will evaluate to false if it is zero so there's no need to explicitly compare it to zero, and the final "Not Positive or Zero" isn't really a possible outcome, as the result of rand will be an integer, which is either positive, negative, or zero by definition.
Parentheses aren't necessary, but they may make it more obvious what the expression is doing.
echo $var ? ($var > 0 ? ' Positive' : ' Negative') : ' Zero';
I'm still getting used to ternary operators and I find it a helpful way of minimizing code. I can make sense out of it if it is simple like the example showed below (example 1)
Example 1
$OrderType = ($name == 'first' ? 'Fred' : ($name == 'last' ? 'Dabo' : 'RAND()'))
This can be read as: if $name is 'first' then use 'Fred' else if $name is 'last' then use 'Dabo' else use 'RAND()'
However I saw this (example 2) on another website and it doesn't make any sense to me.
Example 2
$score = 10;
$age = 20;
echo 'Taking into account your age and score, you are: ',($age > 10 ? ($score < 80 ? 'behind' : 'above average') : ($score < 50 ? 'behind' : 'above average')); // returns 'You are behind'
So can someone explain to me in simple language how this ternary operator will read?
In simple language, that ternary says, if $age > 10, consider 80 a good score, otherwise consider 50 a good score.
Rather than nesting ternaries, consider breaking out the nested logic into its own helper function. I find the following code much more understandable.
function adult_score($score) {
return $score > 80 ? "behind" : "above average";
}
function child_score($score) {
return $score < 50 ? "behind" : "above average";
}
$score = 10;
$age = 20;
echo $age > 10 ? adult_score($score) : child_score($score);
So, you understand a ternary, part before the ? is the if statement, part between ? and : is the "to do if truthy" and the part after : is the "to do if falsey". So if you took that ternary and wrapped the "if" part with an if statement and wrapped the "true" and "false" with curly braces and replaced the : with an else, you end up with this:
if($age > 10){
if($score < 80){
return 'behind';
} else {
return 'above average';
}
} else {
if($score < 50){
return 'behind';
} else {
return 'above average';
}
}
Like others have said though, it is ugly and hard to follow. Unless your goal was to make it hard for others to follow your code, then don't do this. Just please, don't. They are nice for one off if statements, but get confusing fast. Do yourself and any future readers of your code a favor.
This question already has answers here:
Stacking Multiple Ternary Operators in PHP
(11 answers)
Closed 2 years ago.
How do I write a PHP ternary operator with the elseif portion?
I see basic examples with the if and else portions of the PHP ternary operator like this:
echo (true) ? "yes" : "no"; //prints yes
echo (false) ? "yes" : "no"; //prints no
How do I get the "elseif" portion like this into the ternary operator?
<?php
if($result->vocation == 1){
echo "Sorcerer";
}else if($result->vocation == 2){
echo 'Druid';
}else if($result->vocation == 3){
echo 'Paladin';
}else if($result->vocation == 4){
echo 'Knight';
}else if($result->vocation == 5){
echo 'Master Sorcerer';
}else if($result->vocation == 6){
echo 'Elder Druid';
}else if($result->vocation == 7){
echo 'Royal Paladin';
}else{
echo 'Elite Knight';
}
?>
A Ternary is not a good solution for what you want. It will not be readable in your code, and there are much better solutions available.
Why not use an array lookup "map" or "dictionary", like so:
$vocations = array(
1 => "Sorcerer",
2 => "Druid",
3 => "Paladin",
...
);
echo $vocations[$result->vocation];
A ternary for this application would end up looking like this:
echo($result->group_id == 1 ? "Player" : ($result->group_id == 2 ? "Gamemaster" : ($result->group_id == 3 ? "God" : "unknown")));
Why is this bad? Because - as a single long line, you would get no valid debugging information if something were to go wrong here, the length makes it difficult to read, plus the nesting of the multiple ternaries just feels odd.
A Standard Ternary is simple, easy to read, and would look like this:
$value = ($condition) ? 'Truthy Value' : 'Falsey Value';
or
echo ($some_condition) ? 'The condition is true!' : 'The condition is false.';
A ternary is really just a convenient / shorter way to write a simple if else statement. The above sample ternary is the same as:
if ($some_condition) {
echo 'The condition is true!';
} else {
echo 'The condition is false!';
}
However, a ternary for a complex logic quickly becomes unreadable, and is no longer worth the brevity.
echo($result->group_id == 1 ? "Player" : ($result->group_id == 2 ? "Gamemaster" : ($result->group_id == 3 ? "God" : "unknown")));
Even with some attentive formatting to spread it over multiple lines, it's not very clear:
echo($result->group_id == 1
? "Player"
: ($result->group_id == 2
? "Gamemaster"
: ($result->group_id == 3
? "God"
: "unknown")));
Since this would be a common task I would suggest wrapping a switch/case inside of a function call.
function getVocationName($vocation){
switch($vocation){
case 1: return "Sorcerer";
case 2: return 'Druid';
case 3: return 'Paladin';
case 4: return 'Knight';
case 5: return 'Master Sorcerer';
case 6: return 'Elder Druid';
case 7: return 'Royal Paladin';
default: return 'Elite Knight';
}
}
echo getVocationName($result->vocation);
echo ($result ->vocation == 1) ? 'Sorcerer'
: ($result->vocation == 2) ? 'Druid'
: ($result->vocation == 3) ? 'Paladin'
....
;
It’s kind of ugly. You should stick with normal if statements.
How to write a basic PHP Ternary Operator:
($your_boolean) ? 'This is returned if true' : 'This is returned if false';
Example:
$myboolean = true;
echo ($myboolean) ? 'foobar' : "penguin";
foobar
echo (!$myboolean) ? 'foobar' : "penguin";
penguin
A PHP ternary operator with an 'elseif' crammed in there:
$chow = 3;
echo ($chow == 1) ? "one" : ($chow == 2) ? "two" : "three";
three
But please don't nest ternary operators except for parlor tricks. It's a bad code smell.
I'd rather than ternary if-statements go with a switch-case. For example:
switch($result->vocation){
case 1:
echo "Sorcerer";
break;
case 2:
echo "Druid";
break;
case 3:
echo "Paladin";
break;
case 4:
echo "Knight";
break;
case 5:
echo "Master Sorcerer";
break;
case 6:
echo "Elder Druid";
break;
case 7:
echo "Royal Paladin";
break;
default:
echo "Elite Knight";
break;
}
You wouldn’t: it’s messy and hard to read.
You’re looking for the switch statement in the first case. The second is fine as it is but still could be converted for consistency
Ternary statements are much more suited to boolean values and alternating logic.
To be honest, a ternary operator would only make this worse, what i would suggest if making it simpler is what you are aiming at is:
$groups = array(1=>"Player", 2=>"Gamemaster", 3=>"God");
echo($groups[$result->group_id]);
and then a similar one for your vocations
$vocations = array(
1=>"Sorcerer",
2=>"Druid",
3=>"Paladin",
4=>"Knight",
....
);
echo($vocations[$result->vocation]);
With a ternary operator, you would end up with
echo($result->group_id == 1 ? "Player" : ($result->group_id == 2 ? "Gamemaster" : ($result->group_id == 3 ? "God" : "unknown")));
Which as you can tell, only gets more complicated the more you add to it
In addition to all the other answers, you could use switch. But it does seem a bit long.
switch ($result->vocation) {
case 1:
echo 'Sorcerer';
break;
case 2:
echo 'Druid';
break;
case 3:
echo 'Paladin';
break;
case 4:
echo 'Knight';
break;
case 5:
echo 'Master Sorcerer';
break;
case 6:
echo 'Elder Druid';
break;
case 7:
echo 'Royal Paladin';
break;
default:
echo 'Elite Knight';
break;
}
You could also do:
echo "yes" ?: "no" // Assuming that yes is a variable that can be false.
Instead of:
echo (true) ? "yes" : "no";
PHP 8 (Left-associative ternary operator change)
Left-associative ternary operator deprecation https://wiki.php.net/rfc/ternary_associativity.
The ternary operator has some weird quirks in PHP. This RFC adds a deprecation warning for nested ternary statements. In PHP 8, this deprecation will be converted to a compile time error.
1 ? 2 : 3 ? 4 : 5; // deprecated
(1 ? 2 : 3) ? 4 : 5; // ok
source: https://stitcher.io/blog/new-in-php-74#numeric-literal-separator-rfc
I am trying to convert the following code into a Ternary Operator, but it is not working and I am unsure why. I think my problem is that I do not know how to express the elseif operation in ternary format. From my understanding and elseif is performed the same way as an if operation by using the format : (condition) ? 'result'.
if ($i == 0) {
$top = '<div class="active item">';
} elseif ($i % 5 == 0) {
$top = '<div class="item">';
} else {
$top = '';
}
$top = ($i == 0) ? '<div class="active item">' : ($i % 5 == 0) ? '<div class="item">' : '';
$top = ($i == 0) ? '<div class="active item">' : (($i % 5 == 0) ? '<div class="item">' : '');
you need to add parenthesis' around the entire else block
The Ternary Operator doesn't support a true if... else if... else... operation; however, you can simulate the behavior by using the following technique
var name = (variable === 1) ? 'foo' : ((variable === 2) ? 'bar' : 'baz');
I personally don't care for this as I don't find it more readable or elegant. I typically prefer the switch statement.
switch (variable) {
case 1 : name = 'foo'; break;
case 2 : name = 'bar'; break;
default : name = 'bas'; break;
}
Too late probably to share some views, but nevertheless :)
Use if - else if - else for a limited number of evaluations. Personally I prefer to use if - else if - else when number of comparisons are less than 5.
Use switch-case where number of evaluations are more. Personally I prefer switch-case where cases are more than 5.
Use ternary where a single comparison is under consideration (or a single comparison when looping), or when a if-else compare is needed inside the "case" clause of a switch structure.
Using ternary is faster when comparing while looping over a very large data set.
IMHO Its finally the developer who decides the trade off equation between code readability and performance and that in turn decides what out of, ternary vs. if else-if else vs. switch-case, can be used in any particular situation.
//Use this format before reducing the expression to one liner
$var=4; //Change value to test
echo "Format result: ";
echo($var === 1) ? 'one' : //if NB.=> $varname = || echo || print || var_dump(ternary statement inside); can only be (placed at the start/wrapping) of the statement.
(($var === 2) ? 'two' : //elseif
(($var === 3) ? 'three' : //elseif
(($var === 4) ? 'four' : //elseif
'false' //else
))); //extra tip: closing brackets = totalnumber of conditions - 1
// Then echo($var === 1)?'one':(($var === 2)?'two':(($var === 3)?'three':(($var === 4)?'four':'false')));
echo "<br/>";
var_dump("Short result: ", ($var === 1)?'one':(($var === 2)?'two':(($var === 3)?'three':(($var === 4)?'four':'false'))) );
I wan to convert the following code from this
$diff = strtotime($row['start']) - strtotime($current);
if ($diff < 7200) {
echo 'Starts soon';
} else if ($diff <= 0) {
echo 'Started';
} else {
echo 'Starts';
}
to this ?
<?= ($current > $row['start']) ? 'Started' : 'Starts'; ?>
How can ( if possible ) be written in such way ?
It's not very readable, so I wouldn't use it but here you go:
echo ($diff < 7200) ? 'Starts soon': (($diff <= 0) ? 'Started': 'Starts');
That's not really pretty, but you can do it like this :
<?php
$diff = strtotime($row['start']) - strtotime($current);
echo ($diff < 7200 ? 'Start soon' : ($diff <= 0 ? 'Started' : 'Starts'));
?>
Or
<?= ((strtotime($row['start']) - strtotime($current)) < 7200 ? 'Start soon' : ((strtotime($row['start']) - strtotime($current)) <= 0 ? 'Started' : 'Starts')); ?>
There is nothing wrong with an if elseif statement covering a few lines. It makes it easy to read, easy to follow and easy to see what is happening if you are checking your code later - or more importantly if someone else is reading your code.
Remember, it is always easier to write code than it is to read is.
From the documents:
<?php
// on first glance, the following appears to output 'true'
echo (true?'true':false?'t':'f');
// however, the actual output of the above is 't'
// this is because ternary expressions are evaluated from left to right
// the following is a more obvious version of the same code as above
echo ((true ? 'true' : false) ? 't' : 'f');
// here, you can see that the first expression is evaluated to 'true', which
// in turn evaluates to (bool)true, thus returning the true branch of the
// second ternary expression.
?>
It's really not too advisable as it is hard to read and easy to mis-read.
else if can be applied when in else part You add new if.
<?= (($diff < 7200) ? "Starts soon" : (($diff <= 0) ? "Started" : "Starts")); ?>