I have checked a few other questions but they don't really give me the answer I expect..
My code is a like this..
private function handle()
{
if()
{
if(!condition)
{
if(!condition)
{
if(!condition)
{
if(!condition))
{
if(!condition)
{
if(!condition)
{
if(!condition)
{
if(!condition)
{
if(!condition)
{
code
}
return;
}
return;
}
return;
}
return;
}
return;
}
return;
}
return;
}
return;
}
return;
}
}
In my opinion it is readable but messy, sadly I haven't found really a way of making it look 'pretty'. Any ideas?
EDIT: Each return is different.
EDIT2: Gave an answer of my own, thanks everybody!
Conditions can be merged by a && operator..It works form left to right, which means, as soon as the any one starting from left fails, it stops evaluating the condition..
if($a) {
if($b) {
}
}
can be replaced by
if($a && $b) {
}
Use a variable check, or combine the conditions into fewer IF statements.
Variable check like so:
$execute = TRUE;
// Opposite of what you want, e.g. if you want $a only to be TRUE, do $a !== TRUE
if (condition) {
$execute = FALSE;
}
...
// If all the conditions were met, then everything is OK
if($execute === TRUE) {
// code
}else {
// return
}
Edit:
Variable check can be preferably to combining IF statements if you want more control on what returns, e.g. something specific happens if a certain condition fails, which combining conditions can not always allow for.
Like already posted use
if(condition1&&condition2){}
or if this will not work, you can also use function which stops as soon as a condition is true
function some(){
if(!conditon 1){return 0;}
if(condition 2) {return 1;}
}
this provides more power as second if works only if first doesn't satisfy.
You must choose based on your requirements. Sometimes though nested loops are unavoidable.
I thought it out and have found a nice way of doing it, basically I'll make a method for each basic condition, and I'll call them in an if statement with the bitwise AND operator (&), which don't short-circuit.
/**
* nonsql_condition - It means it doesn't check with the database
*
* sql_condition - It means it does check with the database.
*/
if(!$this->nonsql_condition() & !$this->nonsql_condition() & !$this->nonsql_condition() & !$this->nonsql_condition())
{
if(!$this->sql_condition())
{
return error;
}
if(!$this->sql_condition())
{
return error;
}
code;
}
This allows me to use fewer lines of code in my method, plus also not doing unnecessary queries to my database.
Related
What should one use?
This, without else:
function($condition) {
if($condition) {
return true;
}
return false;
}
Or this, with an else:
function($condition) {
if($condition) {
return true;
} else {
return false;
}
}
What are potential drawbacks?
Note: I understand that right solution for this very example would be
function($condition) {
return (boolean)$condition;
}
I like this approach:
function($condition) {
$retValue = false;
if($condition) {
$retValue = true;
}
return $retValue;
}
This way you know where this function will return, (always at the end) which is good for later analyzing. You set a default value and only change it if the condition is right.
With else there is a better readability. However, both the functions are doing the same as the function is terminated by the return function. I find it also safer to use the else if in some cases you can forget using the return function which then go further to return the false.
I would use the else too, for these reasons:
Your code is better readable
In complex code, like when you use if/else within other if/else's, debugging will be much easier.
In some cases it is possible to increase readability by setting "else" aside. Two examples below are eqiuvalent. Second produces less code, though it will suit only when we return values without complex calculations in that block, but again, we can utilize functions to make it usable.
function($a, $b) {
if($a) {
if($a > $b) {
return true;
} else {
return false;
}
} else {
return false;
}
}
function($a, $b) {
if($a) {
if($a > $b) {
return true;
}
}
return false;
}
Note: if not speaking about general cases with more complex conditions assumption, this should fold to:
function($a, $b) {
return ($a and $a > $b);
}
In the first one both true and false will be returned, as when the if statement finishes, it will go and do the very next thing, return false. In the second one, one true OR false will be returned, depending on the condition. Draw backs for the first one would be that you get both true and false returned, which could confuse a function that's only asking for one parameter, and receiving two instead. This is assuming that you include this inside a larger function. I'm not sure why you would want to use the first one though. Hopefully this helps!
What are the best usages of functions that end with "return;" and what are the advantages of writing a function that ends this way?
Example:
function MyFunction() {
// (do something)
return;
}
Thank you
You shouldn't, I would always use return null; so that it is an explicit declaration of what is returned (even if it is null). I'm sure this is also in one of the PSR specs as well, but I don't know them well. To confirm that return; === return null;:
function test() {
return;
}
var_dump(test());
// NULL
As to when you would want to return null;..any function that returns something, should always return something. So maybe if you have a function that gathers and returns a value from a DB, and an error occurs:
public function retrieveData()
{
$data = DB::retrieve();
if(!$data) {
return null;
}
return $data;
}
However, a lot of functions that may have errors just return true/false on success or failure so you won't necessarily use this often.
My main point to drive home: if you don't want/need to return anything, don't return anything.
A return; says only "thats the end". Mostly useful in following examples:
function test($string) {
if(empty($string)) {
return; // If the variable is empty, then stop to work!
}
echo $string;
}
A simple example is that you can write a PHP function that spits out formatted HTML:
function printHeader($value)
{
echo "<h1>$value</h1>";
return;
}
However, since you are not returning anything, the return statement is unnecessary and can be left out.
If you are talking about a empty return;, I can think of one example, if you have code that should be executed under a condition, and more code that should be executed if that condition is not met.
function MyFunction() {
if(a < 1) {
// (do something)
return;
}
// If a >= 0 it executes the code above and the code below
// Do something else
}
This is more or less a readability, maintainability and/or best practice type question.
I wanted to get the SO opinion on something. Is it bad practice to return from multiple points in a function? For example.
<?php
// $a is some object
$somereturnvariable = somefunction($a);
if ($somereturnvariable !== FALSE) {
// do something here like write to a file or something
}
function somefunction($a) {
if (isset($a->value)) {
if ($a->value > 2) {
return $a->value;
} else {
return FALSE;
} else {
// returning false because $a->value isn't set
return FALSE;
}
}
?>
or should it be something like:
<?php
// $a is some object
$somereturnvariable = somefunction($a);
if ($somereturnvariable !== false) {
// do something here like write to a file or something
}
function somefunction($a) {
if (isset($a->value)) {
if ($a->value > 2) {
return $a->value;
}
}
return FALSE
}
?>
As a matter of practice, I always try to return from ONE point in any function, which is usually the final point. I store it in a variable say $retVal and return it in the end of the function.It makes the code look more sane to me.
Having said that, there are circumstances where say, in your function as the first line you check if a var is null and if yes you are returning. In this case, there is no point in holdin on to that variable, then adding additional checks to skip all the function code to return that in the end.
So...in conclusion, both ways works. It always depends on what the situation is and what you are more comfortable with.
I want to return multiple nested functions in PHP. It's possible to break out of multiple loops by adding a number after "break". Eg.
while(1)
while(1)
while(1)
break 3;
Can I do a circuit break while calling a sequence of functions?
Not that I know of, it's also not very healthy of a design, as the parent and grandparent functions in question will never know of the break. You should throw an exception and catch it on the parent, which in turn will throw an exception and catch it on the grandparent etc.
To "break" out of functions, you can use the return.
function somefunction()
{
return;
echo 'This will never get displayed';
}
Another solution would be to add a condition to each while.
while(1 && $isTrue)
while(1 && $isTrue)
while(1 && $isTrue)
$isTrue = false;
break;
Although I don't think this is a very clean approach.
As the manual states break is for loop only.
What I do in such cases is that have an exception return value(or object) and do value check on return value at every function return point to make sure that the situation is propagated or handled appropriately, be careful while doing recursions though, you might completely fold up the tree by mistake....btw if it is a simple exit on error kind of situation you can also use exceptions.
It's possible to return a special result from child functions that indicates a specific condition has been met. WordPress uses WP_Error and is_wp_error() for this sort of operation. Any number of nested functions can check to see if a called function returned an error state, and opt to pass that error up the chain rather than continue with processing.
Example:
function outer() {
$result = inner();
// pass failure back to parent
if( is_wp_error($result) ) {
return $result;
}
// other processing
return $final_result;
}
function inner() {
if( some_condition() ) {
// generate an error
return new WP_Error( 'code', 'message' );
}
return $other_result;
}
$result = outer();
// did we get an error?
if( is_wp_error($result) ) {
echo 'Something went wrong.';
} else {
echo $result;
}
Yes, you can very simply construct a "body-less" while() or if() block. Typically, you will see PSR-12 compliant PHP code using {} to bookend the body of the loop/condition block, but the body is not required. Writing a semicolon at the end of the line will be sufficient and your IDE will not complain about bad syntax.
Returning a truthy value from each function will be an adequate indicator that the following function is authorised for execution.
This will provide the "short circuit" functionality that is desired without creating nested control structures or passing variables into different scopes.
I'll demonstrate with a battery of generic functions:
function echo1T() {
echo "1";
return true;
}
function echo2T() {
echo "2";
return true;
}
function echo3T() {
echo "3";
return true;
}
function echo1F() {
echo "1";
return false;
}
function echo2F() {
echo "2";
return false;
}
function echo3F() {
echo "3";
return false;
}
Code: (Demo with more scenarios)
while (echo1T() && echo2F() && echo3T()); // outputs: 12
if (echo1T() && echo2F() && echo3T()); // outputs: 12
$return = echo1T() && echo2F() && echo3T(); // outputs: 12
var_export($return); // outputs false
I'm stuck in Drupal Panels / PHP Access plugins.
At least, now I found the three conditions to create my final snippet. the purpose of it is to return TRUE; if "condition1 is TRUE" OR "condition2 is TRUE" OR "condition3 is TRUE". I found a lot of similar questions, but the last condition force me to post here to find the right way to do this.
Condition 1:
// At least $view1->result has result.
$view1 = views_get_view('sp_onglet_videos');
$view1->set_display('views-tab-embed_1');
$output1 = $view1->preview();
if ($view1->result) {
return TRUE;
}
Condition 2 (same thing):
// At least $view2->result has result.
$view2 = views_get_view('sp_onglet_audio');
$view2->set_display('views-tab-default');
$output2 = $view2->preview();
if ($view2->result) {
return TRUE;
}
Condition 3 is more complex:
// Checks for content in the field field_txt_videos.
if (isset($contexts['argument_nid_1']->data-> field_txt_videos)) {
$field = $contexts['argument_nid_1']->data-> field_txt_videos;
if (is_null($field)) {
return FALSE;
}
if (is_array($field)) {
foreach ($field as $key => $val) {
if (is_array($val)) {
$field[$key] = array_filter($val);
}
}
$field = array_filter($field);
return count($field);
}
if (is_string($field) && trim($field) == '') {
return FALSE;
}
if ($field) {
return TRUE;
}
return FALSE;
}
I would like to have something clean (and functional) like this:
if ($view1->result && $view2->result && $field) {
return TRUE;
}
But it's to tricky for my php knowledge. Need a little help !
You want to save the result of the 3rd condition (into a variable) and use this result to run your final condition/query. But you can query the 3rd condition if it is a function.
It is better to properly space your code and use plenty of newlines.
However, PHP does have some pretty cool tricks to do assignment inside conditional statements.
if(($view1 = views_get_view('sp_onglet_videos')) AND $view1->set_display('views-tab-embed_1') AND ($output1 = $view1->preview()) AND $view1->result) return TRUE;
However, as you can see this code is a mess - don't do it unless your assignment is really small. Take this simple security check at the top of a PHP file:
<?php defined('BASE_PATH') OR die('Not Allowed');