I wish to run a foreach on a load of ID's.
However each of the items in the foreach is a select query and if it finds more ID's they need to be added to the array that is being run in the foreach.
E.g
$ids = array();
foreach($ids as $id)
{
SELECT id FROM table WHERE otherid = $id;
foreach ($query2->result_array() as $row)
{
array_push($array, $row['id']);
}
}
This is obviously pseudocode so no need to correct my SQL etc. I just need for the foreach to continue if it finds more ID's.
Possible?
I have tried adding an & here -> foreach($ids as &$id) as somebody else on here has suggested in a similar question. This doesn't seem to work.
foreach actually makes a copy of your array to loop though, you will need to use while.
while(list($id_key, $id) = each($ids)){
//your code
$ids[] = $row[id];
}
You should simply be able to just reference the original array ie
foreach ($query2->result_array() as $row)
{
$id[] = $row;
}
This will automatically assign an auto incremented key to the the new array element and add it to the $id array. I assume this is what you are after.
Try to iterate with a variable:
$ids = array();
$i = 0;
while ($i < count($ids)) {
$query2->query(SELECT id FROM table WHERE otherid = $ids[$i]);
foreach ($query2->result_array() as $row)
$ids []= $row['id'];
$i++;
}
For similar problems, I have always used two different arrays. Such code can run a query for every id only one time. I don't think it would be possible with only one array+foreach;
The following code is pretty simple. It keeps finding new ids until there are no new ids.
$ids = array();
$new = array();
$new = $ids;
do {
foreach($new as $n) {
$new = array();
//// HERE PUT YOUR CODE TO RUN A QUERY AND MAYBE PUSH A NEW ID TO $new \\\\
}
$ids = array_merge($ids,$new);
} while (count($new)!==0);
Related
Here's my Query
$rows = $mydb->get_results("SELECT title, description
FROM site_info
WHERE site_id='$id';");
I get something like:
Title1 Desc1
Title2 Desc2
etc.
I want to put that data in array so I do:
$data = array();
foreach ($rows as $obj) {
$data['title'] = $obj->title;
$data['description'] = $obj->description;
}
When I do:
print_r($data);
I only get title and description of first item... Please help :/ I checked and my query returns all what i want to be in array not only the first row.
You are over-writing array indexes each time in iteration.You need to create new indexes each time when you are assigning the values to array.
So either do:-
$data = array();
foreach ($rows as $key=>$obj) { // either use coming rows index
$data[$key]['title'] = $obj->title;
$data[$key]['description'] = $obj->description;
}
Or
$data = array();
$i=0; //create your own counter for indexing
foreach ($rows as $key=>$obj) {
$data[$i]['title'] = $obj->title;
$data[$i]['description'] = $obj->description;
$i++;// increase the counter each time after assignment to create new index
}
For display again use foreach()
foreach ($data as $dat) {
echo $dat['title'];
echo $dat['description'];
}
If the eventual goal is simply to display these values, then you shouldn't bother with re-storing the data as a new multi-dimensional array.
$rows = $mydb->get_results("SELECT title, description FROM site_info WHERE site_id='$id';");
If $id is user-supplied data or from an otherwise untrusted source, you should implement some form of sanitizing/checking as a matter of security. At a minimum, if the $id is expected to be an integer, cast it as an integer (an integer doesn't need to be quote-wrapped).
$rows = $mydb->get_results("SELECT title, description FROM site_info WHERE site_id = " . (int)$id);
When you want to display the object-type data, just loop through $rows and using -> syntax to echo the values.
echo "<ul>";
foreach ($rows as $obj) {
echo '<li>' , $obj->title , ' & ' , $obj->description , '</li>';
}
}
echo "</ul>";
If you have a compelling reason to keep a redundant / restructured copy of the resultset, then you can more simply command php to generate indexes for you.
foreach ($rows as $obj) {
$data[] = ['title' => $obj->title, 'id' => $obj->id];
}
The [] is just like calling array_push(). PHP will automatically assign numeric keys while pushing the associative array as a new subarray of $data.
I use foreach to show items from mysql table, but it lists first items first.
I want to list last items first.
The code:
foreach ( $result as $print ) {
$print->sender_user;
$print->reciever_user;
$print->content;
}
I mean that if I add a new item to mysql table this code should show
it above the other items. But it shows first added item last.
Simple, use array_reverse
http://php.net/manual/en/function.array-reverse.php
array_reverse — Return an array with elements in reverse order
$result = array_reverse($result);
foreach ( $result as $print ) {
$print->sender_user;
$print->reciever_user;
$print->content;
}
Otherwise if it's numerically indexed you can always use for
$len = count($result)-1;
for($i=$len; $i>=0; --$i){
$row = $result[$i];
}
And my favorite
$result = [1,2,3,4];
$row = end($result);
do{
echo $row."\n";
}while($row = prev($result));
Try it here
https://3v4l.org/NINss
And with just while, you cant do prev in the while condition because you lose the last element of the array, so it's a bit lamer.
$result = [1,2,3,4];
$row = end($result);
while($row = current($result)){
echo $row."\n";
prev($result);
}
https://3v4l.org/No1Rb
I think that is about it, I could probably do one with goto but that would be showing off.
I have a simple question. I have an array that has two columns (id, name) that is a result of a MySQL query. I want to store the result of the query into a array variable so i can access each element when i need to.
I am able to store a one dimension array like the following:
$array = array();
while($row = mysqli_fetch_assoc($result))
{
$array[] = $row['name'];
}
How can I store and access a two dimensional array? Also is it best to use a for loop or while loop to store these?
Simply do this:
$array = array();
while($row = mysqli_fetch_assoc($result))
{
$array[] = $row;
}
To access your results you can do this:
$firstResultRow = $array[0];
$firstResultName = $array[0]['id'];
$firstResultName = $array[0]['name'];
This will tell you if a particular row exists:
if(isset($array[$x])) {
$aRow = $row[$x];
// do stuff with $aRow;
}
This will give you a row count for your array:
$rowCount = count($array);
This will set up a loop through your array:
foreach($array as $index => $row) {
$id = $row['id']
$name = $row['name'];
// $index will have the array index of the current row. 0 -> $rowCount - 1
}
Don't specifically store the index of $row but rather store the whole row.
$array = array();
while($row = mysqli_fetch_assoc($result))
{
$array[] = $row;
}
Then $array will have the following structure:
$array = [
[
'id'=> ...,
'name' => ...,
],
...
];
To initially access all of the results from [mysqli_fetch_assoc][1] you will want to use the while loop like you are, mysqli_fetch_assoc will continue to output results until it doesn't have any more data. Then at that point mysqli_fetch_assoc will return NULL. This will signal to your while loop to stop iterating.
Then to access variables inside of your $array, I recommend using foreach.
You could then do:
foreach ($array as $row) {
do something with $row['name'] or $row['id']
}
You could also use a for loop, but it takes more work IMO. Compare the above with this alternative:
for ($i = 0; $i < count($array); $i++) {
$row = $array[$i];
do something with $row['name'] or $row['id']
}
I am fetching data from my DB and they look like this:
[{"0":"1","key-1":"1","1":"1","key-2":"1","2":"1","key-3":"1","3":"1","key-4":"1"}]
where the key-1 are the name of the column. (I only have one entry so).
I want to extract only the column values and save them into a new array that will output like this:
{"key-1":"1","key-2":"1","key-3":"1","key-4":"1"}
I want it to look exactly like this and not : [{"key-1":"1","key-2":"1","key-3":"1","key-4":"1"}]
I tried this:
$cart["key-1"]=$output["key-1"];
where $output is the outcome of the DB that shown first (the one with []).
and the $cart is the new array I want.
Both are declared as:
$cart=array();
$output=array();
and $output[]=$row where row is the result of the DB fetch. How to do it?
Here's one way to do it, I've substituted the database row for a string here, and made use of json_decode() and json_encode()
$data = '[{"0":"1","key-1":"1","1":"1","key-2":"1","2":"1","key-3":"1","3":"1","key-4":"1"}]';
// convert to an array
$data = json_decode($data, true);
// create new array here
$cart = array();
for ($i = 0; $i < count($data); $i++)
{
foreach ($data[$i] as $k => $v)
{
if (strpos($k, 'key') !== FALSE)
{
$cart[$k] = $v;
}
}
}
echo $cart['key-1'] . '<br/>';
echo json_encode($cart);
Output:
1
{"key-1":"1","key-2":"1","key-3":"1","key-4":"1"}
This is a very chaotically asked question.
From what I gathered you want maybe this..?
$cart=array();
foreach ($output as $index=>$value){
if stripos($index,"key-"){
cart[$index]=$value;
}
}
Use mysql_fetch_assoc() to get only column names ;)
while ($row = mysql_fetch_assoc($result_of_query))
{
echo $row['key-1'];
echo $row['key-2'];
}
Say i am having set of rows in a table and each row is having a column called city with some values assigned to it
iam iterating through the result set and i need to assign the list of city values of each row in to an array only unique
foreach($res as $row){
$cities =array();
$cities[] = $row['city'];
//when i say
var_dump($cities);
//Iam not able to get array .how do i do that
$maincities = array('A','B',C)
}
You're resetting $cities to a new array for each row you loop through. Better would be:
$cities = array();
foreach ($res as $row)
{
if ( ! in_array($row['city'], $cities)) {
$cities[] = $row['city'];
}
}
You should but $cities =array();before the foreach loop. Now you are erasing the array at each iteration.
Regards,
Alin
You empty the $cities variable every time in the loop.
It is probably a lot better practise to only have unique cities in your resultset (SELECT DISTINCT city FROM ...)
For example:
$cities =array();
foreach($res as $row){
$cities[] = $row['city'];
}
var_dump($cities);
However it depends on the content of $res
Using keys to eliminate duplicates:
$cities = array();
foreach($res as $row)
$cities[$row['city']] = true;
$cities = array_keys($cities);