So I have the following logic to return a value if it's in the array or just return the original value if it's not:
$trnTitle = $translateMap[$title];
if($trnTitle)
return $trnTitle;
return $title;
Is there a more sleek way to write this? I just feel like there's gotta be like one line I could write instead of calling the variable three times.
Since php 7 you can use the Null-Coalescing operator, if $translateMap[$title] is null, when not filled.
return $translateMap[$title] ?? $title;
See more information here:
http://php.net/manual/en/language.operators.comparison.php#language.operators.comparison.coalesce
I am not sure from your code example what you are trying to achieve for 100%. I see two ways how to look at it.
You do not know if index $title exists in array $translateMap. If it exists you return its value from array or return the index itself:
return $translateMap[$title] ?? $title; <== http://php.net/manual/en/migration70.new-features.php#migration70.new-features.null-coalesce-op
You know that index title exists in array translateMap and you are just checking if it's truthy. If it is truthy you return value from array otherwise index itself.
return $translateMap[$title] ?: $title; <== http://php.net/manual/en/control-structures.if.php#102060
Warning: This would fail if index $title does not exist in array $translateMap
Solution 2 is exactly what you have in your example
You can use the null coalescing operator, which looks like ??.
According to the official PHP documentation,
The null coalescing operator (??) has been added as syntactic sugar for the common case of needing to use a ternary in conjunction with isset(). It returns its first operand if it exists and is not NULL; otherwise it returns its second operand.
So just use this:
return $translateMap[$title] ?? $title
Credit to Nigel Ren's, Vody's, and Manual Otto's comments.
Related
In PHP, to avoid Undefined Index errors, one can write
if(isset $_GET['var1'] && $_GET['var1'] == 'My Matching Text'){
//do stuff
}
But I remember using a function (or language construct) that I think would allow something like this:
if([THE FUNCTION I'M LOOKING FOR]($_GET['var1']) == 'My Matching Text'){
//do stuff
}
What is this function whose name I have forgotten?
Are you thinking of the filter_input function?
if (filter_input(INPUT_GET, 'var1') == 'My Matching Text') {
//do stuff
}
It takes a third argument where you can specify different filter types, which can be useful. The default type doesn't filter at all, but it will return the value (or null if the key isn't set) without an undefined index notice.
I don't know how this compares in terms of performance to using the null coalescing operator like the other answers show, but I would assume this function call would be a little more expensive, so the operator would be a better way to go unless you are going to use one of the filters.
You can use Null coalescing operator (??) in PHP 7+ which allows you to set a 'not defined' value (I've used blank '' in this example)...
if(($_GET['var1']??'') == 'My Matching Text'){
//do stuff
}
This code works in PHP 7.x
$array = ['asda' => ['asdasd']];
$var = $array['asda']['asdasd'] ?? "yes!";
echo $var;
If we replace ?? with ?: as we have in older PHP version, this code will not work, for example:
$array = ['asda' => ['asdasd']];
$var = $array['asda']['asdasd'] ? $array['asda']['asdasd'] : "yes!";
echo $var;
It means, we will get an error like:
Notice</b>: Undefined index: asdasd in <b>[...][...]</b> on line
So, can we use the first example in PHP 7.x without afraid about anything strange/unexpected in behind? I mean, is it safe to use this instead, for example, array_key_exists or isset
Use isset() to test if the element exists.
$var = isset($array['asda']['asdasd']) ? $array['asda']['asdasd'] : "yes!";
The old :? conditional operator is a simple if/then/else -- it tests the truthiness of the first expression, and then returns either the second or third expression depending on this. The test expression is executed normally, so if it involves undefined variables, indexes, or properties you'll get a normal warning about it.
The new ?? null-coalescing operator, on the other hand, tests whether the first expression is defined and not NULL, not just whether it's truthy. Since it does it's own check for whether the expression is defined, it doesn't produce a warning when it's not. It's specifically intended as a replacement for the isset() conditional.
See PHP ternary operator vs null coalescing operator
I have a function to populate an Object.
public static function populateObj($data) {
$obj = new Obj();
$obj->setVal1($data['val1']);
$obj->setVal2($data['val2']);
$obj->setId($data['id']);
return $obj;
}
If all values are given with the parameter $data it works fine. But if someting is missing it throws an error.
Is there a shorter and easier or better way to set null as default than this:
$data['val1'] ? $obj->setVal1($data['val1']) : $obj->setVal1(null);
...
You can merge with a default array, then $data will contain all of those keys:
$data = array_merge(['val1'=>null, 'val2'=>null, 'id'=>null], $data);
In PHP >= 7.0 you can use the Null Coalescing Operator:
$obj->setVal1($data['val1'] ?? null);
That is perhaps the fastest (fewest typed words) way to do it. Another that may be faster, if it is worth it to you is to make a class and a constructor with default values. array_pad() with array_merge() may also be worth looking at, depending on your application.
In PHP 7+ you can use ?? a.k.a null coalesce
$obj->setVal1($data['val1']??null);
$obj->setVal2($data['val2']??null);
$obj->setId($data['id']??null);
See an example here
The null coalescing operator (??) has been added (in PHP7) as syntactic sugar for the common case of needing to use a ternary in conjunction with isset(). It returns its first operand if it exists and is not NULL; otherwise it returns its second operand.
Is there a way to set object parameter value to empty string or null if object does not exist instead of fatal error?
Lets say i have this in my view:
<div> <?php $car->name; ?> </div
And there is a chance that car is empty object in some cases.
I just could write my own function that checks object and return object parameter or empty string, but i want to know if there is a default way to do this.
Another way would be use shorthand if statement, as in
($car) ? $car->name : "";
but it is too long to but in view IMHO.
You have a few different options
The long way is using one of the following functions in an if statement:
isset
empty
example
if(!isset($car->name)) {
return 'No car';
}
using empty
if(empty($car->name)) {
return 'No car';
}
Or you can combine both if you really wanted.
You can also use them in shorthand as you have done above or using the isset and or empty functions.
If you are using PHP version 7 you can use a new feature that shipped with it called Null coalescing operator (??)
Example:
echo $car->name ?? 'No car';
It returns its first operand if it exists and is not NULL; otherwise it returns its second operand.
I am running PHP7 and use it daily!
I was wondering whether is another way to check if a variable coming from user input is set and not null, besides (the obvious choice) isset().
In some cases, we may not be using $_POST to get the value, but some similar custom function. isset() can not be used on the result of a function call, so an alternative way to perform the same check must be made. Now, isset() verifies two things:
Whether the value was set.
Whether the value is null. But there is some difference between assigning a variable the null value ( $variable = NULL; ) and getting a null value due to empty input fields. Or at least so I read.
So, is there a good way of checking both these requirements without using isset() ?
The equivalent of isset($var) for a function return value is func() === null.
isset basically does a !== null comparison, without throwing an error if the tested variable does not exist. This is a non-issue for function return values, since a) functions must exist (or PHP will exit with a fatal error) and b) a function always returns something, at least null. So all you really need to do is to check for null, no isset necessary.
I've written about this extensively here: The Definitive Guide To PHP's isset And empty.
Beyond this, it depends on what exactly you want to check:
test if a key was submitted via GET/POST: isset($_POST['key'])
test if there's a value and whether it's not == false: !empty($_POST['key'])
test if it's a non-empty string: isset($_POST['key']) && strlen($_POST['key'])
perhaps much more complex validations: filter_input
Here are some options...
PHP 7.4+ : null coalescing assignment operator
$variable ??= '';
PHP 7.0+ : null coalescing operator
$variable = $var ?? '';
PHP 5.3+ : ternary operator
isset($variable) ?: $var = '';
You can also use !empty() in place of isset()
the function !empty() works for both isset() and check whether the value of any string is not null, 0 or any empty string.
I usually prefer !empty() whenever I need to compare variable existence or in terms of its value.
The best way is isset but if you insist ... try empty() and strlen() Function to check wether it is empty or string lenghth is bigger than so many characters.
strlen() returns a number, length of the variable passed to it.
empty() checks if it has character in it or if it is null. with empty() you have to be becareful because some functions return 0 or false which is not considered empty.
if(!empty($var))....
OR
if(strlen($var)>2)...
I do it in most cases like this:
$v = my_func();
if (isset($v) and $v) {
...
}