I am new on coding can you help me with accessing this I am stuck here:
foreach($questions_answers as $correct) {
dd($correct->answers);
}
And this is what I am getting so far but I want to access correct how can I achieve that..?
You loop over the items in the collection and then you can access the individual properties:
foreach($questions_answers as $questions_answer) {
dd($questions_answer->correct);
}
try:
foreach ($questions_answers as $correct) {
foreach ($correct->answers as $answer) {
if ($answer->correct == 1) {
dd($answer);
}
}
}
I'm struggling in finding a way to correctly do this logic.
If (this thing is null)
Skip it
Else
Don't skip it
I tried with if/else and while loops but each one will crash the program. I test something like this:
(inside a foreach)
if($value->getThing() == NULL) {
//HOW TO SKIP???
//I try to 'set' this thing
$value->setThing(0); //BUT IT Doesn't work because it's an associated object...
} else {
$value->getThing();
}
And tried this:
(inside foreach)
while ($value->getThing() != NULL) {
$value->getThing();
//Do Calculation...
}
Both just crash when it gets to the thing thats null. I know why but I can't figure out how to skip the null thing.
and if you can't tell, I'm a newbie. But I'm learning.
EDIT: The thing is null in the db.
Try this code :
foreach($values as $value){
if(!is_null($value->getThing())){
#do calculation
}
}
For "skipping" an entry you can use "continue".
foreach($array as $key => $value){
if($value['foo'] == null){
continue;
}
//Do the calculation
}
..or perhaps:
foreach($array as $key => $value){
if(is_null($value['foo'])){
//Null value treatment
continue;
}
//Do the calculation
}
What you are actually looking for is the NOT IS Operator as I like to call it.
foreach ($things as $thing) {
if (!is_null($thing)) {
// Do the stuff that you wanna do
}
}
The above dummy code teaches that you do not have to use an else. It also shows the is_null() function which checks if something is actually NULL. Furthermore it shows the ! operator that can also be translated to NOT IS.
What !is_null() actually says is: "If the return value of this function, variable and so on is not NULL..."
Good luck.
Try this:
$names = file('name.txt');
// To check the number of lines
echo count($names).'<br>';
foreach($names as $name) {
echo $name.'<br>';
}
It often happens to me to handle data that can be either an array or a null variable and to feed some foreach with these data.
$values = get_values();
foreach ($values as $value){
...
}
When you feed a foreach with data that are not an array, you get a warning:
Warning: Invalid argument supplied for foreach() in [...]
Assuming it's not possible to refactor the get_values() function to always return an array (backward compatibility, not available source code, whatever other reason), I'm wondering which is the cleanest and most efficient way to avoid these warnings:
Casting $values to array
Initializing $values to array
Wrapping the foreach with an if
Other (please suggest)
Personally I find this to be the most clean - not sure if it's the most efficient, mind!
if (is_array($values) || is_object($values))
{
foreach ($values as $value)
{
...
}
}
The reason for my preference is it doesn't allocate an empty array when you've got nothing to begin with anyway.
How about this one? lot cleaner and all in single line.
foreach ((array) $items as $item) {
// ...
}
I usually use a construct similar to this:
/**
* Determine if a variable is iterable. i.e. can be used to loop over.
*
* #return bool
*/
function is_iterable($var)
{
return $var !== null
&& (is_array($var)
|| $var instanceof Traversable
|| $var instanceof Iterator
|| $var instanceof IteratorAggregate
);
}
$values = get_values();
if (is_iterable($values))
{
foreach ($values as $value)
{
// do stuff...
}
}
Note that this particular version is not tested, its typed directly into SO from memory.
Edit: added Traversable check
Please do not depend on casting as a solution,
even though others are suggesting this as a valid option to prevent an error, it might cause another one.
Be aware: If you expect a specific form of array to be returned, this might fail you. More checks are required for that.
E.g. casting a boolean to an array (array)bool, will NOT result in an empty array, but an array with one element containing the boolean value as an int: [0=>0] or [0=>1].
I wrote a quick test to present this problem.
(Here is a backup Test in case the first test url fails.)
Included are tests for: null, false, true, a class, an array and undefined.
Always test your input before using it in foreach. Suggestions:
Quick type checking: $array = is_array($var) or is_object($var) ? $var : [] ;
Type hinting arrays in methods before using a foreach and specifying return types
Wrapping foreach within if
Using try{}catch(){} blocks
Designing proper code / testing before production releases
To test an array against proper form you could use array_key_exists on a specific key, or test the depth of an array (when it is one !).
Always extract your helper methods into the global namespace in a way to reduce duplicate code
Try this:
//Force array
$dataArr = is_array($dataArr) ? $dataArr : array($dataArr);
foreach ($dataArr as $val) {
echo $val;
}
;)
$values = get_values();
foreach ((array) $values as $value){
...
}
Problem is always null and Casting is in fact the cleaning solution.
foreach ($arr ?: [] as $elem) {
// Do something
}
This doesen't check if it is an array, but skips the loop if the variable is null or an empty array.
Update from PHP 7.0 you should use the null coalescing operator:
foreach ($arr ?? [] as $elem) {
// Do something
}
This would solve the warning mentioned in the comment (here a handy table that compares ?: and ?? outputs).
First of all, every variable must be initialized. Always.
Casting is not an option.
if get_values(); can return different type variable, this value must be checked, of course.
If you're using php7 and you want to handle only undefined errors this is the cleanest IMHO
$array = [1,2,3,4];
foreach ( $array ?? [] as $item ) {
echo $item;
}
As of PHP >= 7.1.0 use is_iterable
https://www.php.net/manual/en/function.is-iterable.php
if (is_iterable($value)) {
foreach ($value as $v) {
...
}
}
More concise extension of #Kris's code
function secure_iterable($var)
{
return is_iterable($var) ? $var : array();
}
foreach (secure_iterable($values) as $value)
{
//do stuff...
}
especially for using inside template code
<?php foreach (secure_iterable($values) as $value): ?>
...
<?php endforeach; ?>
Warning invalid argument supplied for foreach() display tweets.
go to /wp-content/plugins/display-tweets-php.
Then insert this code on line number 591, It will run perfectly.
if (is_array($tweets)) {
foreach ($tweets as $tweet)
{
...
}
}
This warning is happening because the array that you want use is empty, you can use of below condition:
if ($your_array != false){
foreach ($your_array as $value){
echo $value['your_value_name'];
}
}
There seems also to be a relation to the environment:
I had that "invalid argument supplied foreach()" error only in the dev environment, but not in prod (I am working on the server, not localhost).
Despite the error a var_dump indicated that the array was well there (in both cases app and dev).
The if (is_array($array)) around the foreach ($array as $subarray) solved the problem.
Sorry, that I cannot explain the cause, but as it took me a while to figure a solution I thought of better sharing this as an observation.
Exceptional case for this notice occurs if you set array to null inside foreach loop
if (is_array($values))
{
foreach ($values as $value)
{
$values = null;//WARNING!!!
}
}
I'll use a combination of empty, isset and is_array as
$array = ['dog', 'cat', 'lion'];
if (!empty($array) && isset($array) && is_array($array) {
//loop
foreach ($array as $values) {
echo $values;
}
}
Use is_array function, when you will pass array to foreach loop.
if (is_array($your_variable)) {
foreach ($your_variable as $item) {
//your code
}
}
How about this solution:
$type = gettype($your_iteratable);
$types = array(
'array',
'object'
);
if (in_array($type, $types)) {
// foreach code comes here
}
What about defining an empty array as fallback if get_value() is empty?
I can't think of a shortest way.
$values = get_values() ?: [];
foreach ($values as $value){
...
}
<?php
if (isset($_POST['checkbox'])) {
$checkbox = $_POST['checkbox'];
foreach ($checkbox as $key) {
echo $key . '<br>';
}
}
?>
<input type="checkbox" name="checkbox[]" value="red">red <br>
<input type="checkbox" name="checkbox[]" value="green">green <br>
I couldn't find anything that answers my question so here it is:
I need to have a foreach loop to take each function inside of an array and run each and check if it returns true, simple enough. Like this:
$array_name = array(function1(),function2(),function3());
foreach($array_name as &$value) {
/* run each function */
/* checks if it returns true */
}
This may be so easy I just don't see it, but I can't find any definitive documentation on how to correctly implement this.
$array_name = array('function1', 'function2', 'function3');
foreach($array_name as $value) {
if($value()) {
// do stuff if the function returned a true-ish value
}
}
Another option to call the function would be call_user_func($value).
Try it:
$array_name = array('function1','function2','function3');
foreach($array_name as &$value) {
if(function_exists($value) && ($value())) {
//function exists and it returns true
}
}
Try to adopt things from : http://php.net/manual/en/functions.variable-functions.php
foreach($functionName as $arg) {
$arg();
}
But as you question contains:
$array_name = array(function1(),function2(),function3());
Make sure "function1()" is used in your array. So we can have:
foreach($functionName as $arg) {
$check = $arg;
if($check != false){
//Do stuff here
}else{
//Do stuff here
}
}
I have an object in PHP and I'm using a
foreach ($items as $item)
to iterate through the items. However, $item contains another object called $item, which contains the $type variable whose value I need to access. How can I access the value of $type? What I want to do is:
foreach($items as item){
if($item->item->type == 'this'){
//do this
} elseif ($item->item->type == 'that'){
//do that
}
}
But $item->item->type isn't picking up that value. How can I access it and use it for my function?
have you tired:
foreach($items as item){
if($item->type == 'this'){
//do this
} elseif ($item->type == 'that'){
//do that
}
}
or you can debug your code to find out what is going on:
foreach($items as item){
print_r($item);
}
and then you can see what kind of childs this $item has.