I have read a lot of posts and have not been able to find a solution to my issue.
I have a $_POST array named "Water", $_POST['Water'] and its contents are:
[Water] => Array ( [0] => 55.0 [1] => 22 )
Is it possible to use the name of the post inside a foreach loop so the $key could use the name "Water":
foreach($_POST['Water'] as $key => $val) {
$fields[] = "$field = '$val'";
//echo "Key: $key, Value: $val<br/>\n";
}
Many thanks for your time.
Not really. foreach() operates on the contents of an array. Whatever actually contains that array is outside of foreach's view. If you want to dynamically use the Water key elsewhere, you'll have to do that yourself:
$key = 'Water'
foreach($_POST[$key] as $val) {
$fields[] = "$key = '$val'";
}
If I read this right you basically want $field='water' inside the foreach. This can be done be rethinking the way we build the foreach.
You simply need to make the field value a variable and pass use that rather everywhere the value is needed.
$field = 'Water';
foreach($_POST[$field] as $key => $val) {
$fields[] = "$field = '$val'";
//echo "Key: $key, Value: $val<br/>\n";
}
The advantage of this approach is that if you change your mind and the $_POST key is later called, "liquid" one single line needs to be edited and that is all. Furthermore, if your foreach were part of a function $field could be a function parameter. In a roundabout way, you are actually getting pretty close to some code reuse principles.
Related
I have this code
if (isset($_POST['submit2']))
{
foreach ($_POST['check_list'] as $key) {
$input = implode(",", $key);
}
} /*end is isset $_POST['submit2'] */
echo $input;
it produces the error " implode(): Invalid arguments passed " when I change the implode arguments to implode(",", $_POST['check_list']) it works as intended.
Can someone clarify why? As far as I understand the $key variable should be the same as the $_POST['submit2'] isn't that what the as in the foreach does?
Sorry if it's a silly question, I'm self taught and sometimes details like that are hard to find online.
You seem confused at several levels, so let me clarify some of them:
You said 'As far as I understand the $key variable should be the same as the $_POST['submit2'] isn't that what the as in the foreach does?'. The answers are NO and NO:
The $key variable outside the foreach loop will contain the last element of the array that's stored in $_POST['check_list'], $_POST['submit2'] seems to be only used to check if is set and nothing else in your piece of code. What foreach does is to traverse any iterator variable (an array in your case) and set the current item in a variable ($key) in your case. So after the loop, $key will contain the last element of that array. For more information refer to the docs: [http://php.net/manual/en/control-structures.foreach.php]
implode expects the second parameter to be an array, it seems you're not providing an array, but any other type. Is the last item of $_POST['check_list'] actually an array?
If you're trying to 'glue' together all items of $_POST['check_list'], you don't need to iterate, you just use implode on that one: $input = implode(",", $_POST['check_list']);. Otherwise, i'm not sure what are you trying to do.
Maybe if you explain what are you trying to do, we can help better.
Foreach already iterates trough your values. You can either get the value and echo it from there or you can add it to another array input if thats what you need:
if (isset($_POST['submit2']))
{
foreach ($_POST['check_list'] as $key => $value) {
$input[] = 'Value #'. $key .' is ' . $value;
}
}
echo implode(",", $input);
You are saying that $_POST['check_list'] is an array if implode() works on it, so no need to loop to get individual items. To implode() the values:
echo implode(',', $_POST['check_list']);
To implode() the keys:
echo implode(',', array_keys($_POST['check_list']));
foreach() iterates over an array to expose each item and get the individual values and optionally keys one at a time:
foreach($_POST['check_list'] as $key => $val) {
echo "$key = $value<br />";
}
implode function needs array as second argument. You are passing string value as second argument. That's why it's not working.
Upon posting a form using _GET I would like to get the input name
See below part of url upon submit
.php?14=0&15=0&16=0&17=0&18=0&19=0
I know how to get the variable E.G:
$14=$_GET["14"];
Which is 0
However is it possible to do this and get the input name (eg 14) and then turn these into variables? (To save the input name to the DB)
To get all the $_GET parameters, you can do:
foreach($_GET as $key => $value){
echo "Key is $key and value is $value<br>";
}
This will output each key (14, 15, 16 etc) and value (0, 0, 0 etc).
To bind a variable name with a variable string, look at variable variables:
foreach($_GET as $key => $value){
$$key = $value;
}
As a result, you will have the following variables with the following values:
$14 = 0;
$15 = 0;
$16 = 0;
// etc...
Alternatively (as you don't necessarily know what the key/value pairs would be), you could create an empty array and add these keys and values to it:
foreach($_GET as $k => $v){
$arr[$k] = $v;
}
The resulting array will be:
$arr[14] = 0;
$arr[15] = 0;
$arr[16] = 0;
// etc...
Solution using single loop (Update):
If you're just using question/answer single time you can do it in single loop like this,
<?php
foreach($_GET as $key => $value){
$question = $key;
$answer = $value;
// Save question and answer accordingly.
}
If you will be using question answer to perform other things, use the following method.
You can get all the keys using array_keys(), where $_GET is an array.
Use it like this,
<?php
$keys=array_keys($_GET);
print_r($keys); // this will print all the keys
foreach($keys as $key) {
// access each key here with $key
}
Update:
You can make a pair of question,answer array and put it in the main array to insert it in the database like this,
<?php
$mainArray=array();
$keys=array_keys($_GET);
foreach($keys as $key) {
// access each key here with $key
$questionAnswerArray=array();
$questionAnswerArray["question"]=$key;
$questionAnswerArray["answer"]=$_GET[$key];
$mainArray[]=$questionAnswerArray;
}
// Now traverse this array to insert the data in database.
foreach($mainArray as $questionanswer) {
echo $questionanswer["question"]; //prints the question
echo $questionanswer["answer"]; // prints the answer.
}
I have an array like this:
array(
'firstName' => 'Joe',
'lastName' => 'Smith'
)
I need to loop over every element in my array and in the end, the array should look like this:
array(
'FirstName' => 'Joe',
'LastName' => 'Smith'
)
Failed idea was:
foreach($array as $key => $value)
{
$key = ucfirst($key);
}
This obviously will not work, because the array is not passed by reference. However, all these attempts also fail:
foreach(&$array as $key => $value)
{
$key = ucfirst($key);
}
foreach($array as &$key => $value)
{
$key = ucfirst($key);
}
Pretty much at my wits end with this one. I'm using Magento 1.9.0.1 CE, but that's pretty irrelevant for this problem. If you must know, the reason I have to do this is because I have a bunch of object that's I'm returning as an array to be assembled into a SOAP client. The API I'm using requires the keys to begin with a capital letter...however, I don't wish to capitalize the first letter of my object's variable names. Silly, I know, but we all answer to someone, and that someone wants it that way.
unset it first in case it is already in the proper format, otherwise you will remove what you just defined:
foreach($array as $key => $value)
{
unset($array[$key]);
$array[ucfirst($key)] = $value;
}
You can't modify the keys in a foreach, so you would need to unset the old one and create a new one. Here is another way:
$array = array_combine(array_map('ucfirst', array_keys($array)), $array);
Get the keys using array_keys
Apply ucfirst to the keys using array_map
Combine the new keys with the values using array_combine
The answers here are dangerous, in the event that the key isn't changed, the element is actually deleted from the array. Also, you could unknowingly overwrite an element that was already there.
You'll want to do some checks first:
foreach($array as $key => $value)
{
$newKey = ucfirst($key);
// does this key already exist in the array?
if(isset($array[$newKey])){
// yes, skip this to avoid overwritting an array element!
continue;
}
// Is the new key different from the old key?
if($key === $newKey){
// no, skip this since the key was already what we wanted.
continue;
}
$array[$newKey] = $value;
unset($array[$key]);
}
Of course, you'll probably want to combine these "if" statements with an "or" if you don't need to handle these situations differently.
This might work:
foreach($array as $key => $value) {
$newkey = ucfirst($key);
$array[$newkey] = $value;
unset($array[$key]);
}
but it is very risky to modify an array like this while you're looping on it. You might be better off to store the unsettable keys in another array, then have a separate loop to remove them from the original array.
And of course, this doesn't check for possible collisions in the aray, e.g. firstname -> FirstName, where FirstName already existed elsewhere in the array.
But in the end, it boils down to the fact that you can't "rename" a key. You can create a new one and delete the original, but you can't in-place modify the key, because the key IS the key to lookup an entry in the aray. changing the key's value necessarily changes what that key is pointing at.
Top of my head...
foreach($array as $key => $value){
$newKey = ucfirst($key);
$array[$newKey] = $value;
unset($array[$key]);
}
Slightly change your way of thinking. Instead of modifying an existing element, create a new one, and remove the old one.
If you use laravel or have Illuminate\Support somewhere in your dependencies, here's a chainable way:
>>> collect($array)
->keys()
->map(function ($key) {
return ucfirst($key);
})
->combine($array);
=> Illuminate\Support\Collection {#1389
all: [
"FirstName" => "Joe",
"LastName" => "Smith",
],
}
So I don't think I'm making full use of the foreach loop. Here is how I understand foreach.
It goes like foreach(arrayyouwanttoloopthrough as onevalueofthatarray)
No counter or incrementing required, it automatically pulls an array, value by value each loop, and for that loop it calls the value whatever is after the "as".
Stops once it's done with the array.
Should basically replace "for", as long as dealing with an array.
So something I try to do a lot with foreach is modify the array values in the looping array. But in the end I keep finding I have to use a for loop for that type of thing.
So lets say that I have an array (thing1, thing2, thing3, thing4) and I wanted to change it....lets say to all "BLAH", with a number at the end, I'd do
$counter = 0;
foreach($array as $changeval){
$counter++;
$changeval = "BLAH".$counter;
}
I would think that would change it because $changeval should be whatever value it's at for the array, right? But it doesn't. The only way I could find to do that in a] foreach is to set a counter (like above), and use the array with the index of counter. But to do that I'd have to set the counter outside the loop, and it's not even always reliable. For that I'd think it would be better to use a for loop instead of foreach.
So why would you use foreach over for? I think I'm missing something here because foreach has GOT to be able to change values...
Thanks
OH HEY One more thing. Are variables set in loops (like i, or key) accessible outside the loop? If I have 2 foreach loops like
foreach(thing as value)
would I have to make the second one
foreach(thing2 as value2) ]
or else it would have some problems?
You can use a reference variable instead:
foreach ($array as &$value)
{
$value = "foo";
}
Now the array is full of foo (note the & before $value).
Normally, the loop variable simply contains a copy of the corresponding array element, but the & (ampersand) tells PHP to make it a reference to the actual array element, rather than just a copy; hence you can modify it.
However, as #Tadeck says below, you should be careful in this case to destroy the reference after the loop has finished, since $value will still point to the final element in the array (so it's possible to accidentally modify it). Do this with unset:
unset($value);
The other option would be to use the $key => $value syntax:
foreach ($array as $key => $value)
{
$array[$key] = "foo";
}
To answer your second question: yes, they are subsequently accessible outside the loop, which is why it's good practice to use unset when using reference loop variables as in my first example. However, there's no need to use new variable names in subsequent loops, since the old ones will just be overwritten (with no unwanted consequences).
You want to pass by reference:
$arr = array(1, 2, 3, 4);
foreach ($arr as &$value)
{
$value = $value * 2;
}
// $arr is now array(2, 4, 6, 8)
The extended foreach syntax is like this:
foreach ($array as $key => $value) {
}
Using the $key, you can index the original array:
foreach ($array as $key => $value) {
$array[$key] = "BLAH";
}
Incrementing from 0 to ...
foreach($array as $changeval){
if (!isset($counter)) { $counter = 0; }
$counter++;
$changeval = "BLAH".$counter;
}
Using the index/key of the ARRAY
foreach($array as $key => $changeval){
$changeval = "BLAH".$key;
}
You can use the key when looping with foreach:
foreach ($array as $key => $value)
{
$array[$key] = "foo";
}
But note that using a reference like Will suggested will be faster for such a case - but anyway, the $key => $value-syntax is quite useful sometimes.
Often, I will have an array holding a set of values each of which I need to process. Sometimes, the array will only hold a single set, in which case each value needs to be put through the process. Other times, the array will hold many sets, in which case each value will be an array and each value of those arrays will need to be processed. Here is an example:
foreach($array as $key => $value) {
if(is_array($value)) {
foreach($value as $subkey => $subvalue) {
//Process $subvalue here
}
}
else {
//Process $value here
}
}
The problem is that the code for processing $value/$subvalue is identical except that it operates on a different variable. One way to simplify this would be to put that code into a function but it still seems inelegant to have to call it twice. Furthermore, that would leave quite a lot of code (the foreach loops and array test) outside of that function. For example, say the process is validation, I don't want to have to write two foreach loops and an array test whenever I want to call my validation function.
Is there a simpler way of doing this?
You can use a RecursiveArrayIterator to iterate over the values in the array, e.g.
$iterator = new RecursiveIteratorIterator(
new RecursiveArrayIterator($yourArray),
RecursiveIteratorIterator:SELF_FIRST);
Then just foreach over it. Further reading:
http://www.phpro.org/tutorials/Introduction-to-SPL.html#7
Wrap the single value into an array, then proceed as usual:
foreach($array as $key => $value) {
if(!is_array($value)) $value = array($value);
foreach($value as $subkey => $subvalue) {
//Process $value/$subvalue here
}
}
Alternatively you can create a function that handles the processing of single items, then call that same function from each branch. You'll still end up saving writing the process twice.