array looping strange behavior in php - php

I have an indexed array which I've generated from an associative array with this code
$index_arr = array();
foreach($assoc_arr as $key => $val ){
$index_arr .= $val;
}
when I print it with print_r($index_arr); it works fine. But when I try to print it with foreach I get an error "Invalid argument supplied for foreach()"
foreach($index_arr as $one){
echo "one: $one<br />";
}
I'm pretty sure this is the right syntax or am I too tired at this time of day?

You turn the array into a string by using .= operator on it. You want to use:
$index_arr[] = $val;
To append to the end.
Also in this particular case, you can just do:
$index_arr = array_values($assoc_arr);
This does exactly what your loop does.

When you did $index_arr .= $val; PHP did a String operation. You need to do $index_arr[]=$val;

Needs to be this:
$index_arr = array();
foreach($assoc_arr as $key => $val ){
$index_arr[] = $val;
}
Also
foreach($index_arr as $key=>$data){
echo "Key: ".$key." Data: ".$data."<br />";
}

$index_arr .= $val;
should be
$index_arr[] = $val;

Related

concatinating two array elements with a string within a foreach loop

I am trying to combine two array elements with the string "OR" and create one string of elements.
The array looks like this:
$myarray = array(2282396,1801345)
This is the code i have used.
$bool = ' OR ';
foreach($myarray as $element){
echo $element .= $bool;
}
I trying to get this output after looping using a foreach loop.
2282396 OR 1801345
However, the output i get looks like this:
2282396 OR 1801345 OR
How do i get rid of the 'OR' after the second element? Thanks in advance
You have to check if you're in the first/last iteration or not.
$first = true;
$bool = ' OR ';
foreach ($myarray as $element) {
if (!$first) {
echo $bool;
}
echo $element;
$first = false;
}
If your array is indexed by numeric indexes 0-x, you an use
$bool = ' OR ';
foreach ($myarray as $key => $element) {
if ($key > 0) {
echo $bool;
}
echo $element;
}
Use implode as:
echo implode(" OR ", $myarray);
Documentation implode
Live example: 3v4l

modify key in a foreach loop php

I want to change the value of the $key because I have array_splice inside the loop which change the position of my values so - it mess up the value I need in a specific place.
I tried $key-- but it doesn't work.
for example when I print the $key after I do echo $key it's fine but when I echo $key just after the foreach loop I get the worng value.
Any ideas?
foreach ($cut as $key => $value) {
echo "foreach key:".$key."<br>";
if(in_array($value,$operators))
{
if($value == '||')
{
echo "found || in position:".$key."<br>";
if(($key+1<sizeof($cut)))
{
$multi = new multi;
echo "<br>"."key-1: ";
print_r($cut[$key-1]);
echo"<br>";
echo "<br>"."key+1: ";
print_r($cut[$key+1]);
echo"<br>";
$res = $multi->orex($cut[$key-1],$cut[$key+1],$numString);
$cut[$key-1]= $res;
array_splice($cut,$key,1);
array_splice($cut,$key,1);
$key--; //here trying to change the key
echo "new string:";
print_r($cut);
echo "<br>";
echo "key:".$key."<br>";
}
}
}
}
Updated
I don't think it is a good idea to change the array itself inside the foreach loop. So please crete another array and fill data into it, which will be your result array. This method works well when your array data is not big, in other words, most situations.
Origin
I don't know what do you mean. Let me give it a guess...
You want:
foreach($arr as $key=>$val){
$newkey = /* what new key do you want? */
$arr[$newkey] = $arr[$key];
unset($arr[$key]);
}

Retrieving array keys from JSON input

I have this array:
$json = json_decode('
{"entries":[
{"id": "29","name":"John", "age":"36"},
{"id": "30","name":"Jack", "age":"23"}
]}
');
and I am looking for a PHP "for each" loop that would retrieve the key names under entries, i.e.:
id
name
age
How can I do this?
Try it
foreach($json->entries as $row) {
foreach($row as $key => $val) {
echo $key . ': ' . $val;
echo '<br>';
}
}
In the $key you shall get the key names and in the val you shal get the values
You could do something like this:
foreach($json->entries as $record){
echo $record->id;
echo $record->name;
echo $record->age;
}
If you pass true as the value for the second parameter in the json_decode function, you'll be able to use the decoded value as an array.
I was not satisfied with other answers so I add my own. I believe the most general approach is:
$array = get_object_vars($json->entries[0]);
foreach($array as $key => $value) {
echo $key . "<br>";
}
where I used entries[0] because you assume that all the elements of the entries array have the same keys.
Have a look at the official documentation for key: http://php.net/manual/en/function.key.php
You could try getting the properties of the object using get_object_vars:
$keys = array();
foreach($json->entries as $entry)
$keys += array_keys(get_object_vars($entry));
print_r($keys);
foreach($json->entries[0] AS $key => $name) {
echo $key;
}
$column_name =[];
foreach($data as $i){
foreach($i as $key => $i){
array_push($column_name, $key);
}
break;
}
Alternative answer using arrays rather than objects - passing true to json_decode will return an array.
$json = '{"entries":[{"id": "29","name":"John", "age":"36"},{"id": "30","name":"Jack", "age":"23"}]}';
$data = json_decode($json, true);
$entries = $data['entries'];
foreach ($entries as $entry) {
$id = $entry['id'];
$name = $entry['name'];
$age = $entry['age'];
printf('%s (ID %d) is %d years old'.PHP_EOL, $name, $id, $age);
}
Tested at https://www.tehplayground.com/17zKeQcNUbFwuRjC

How can I easily remove the last comma from an array?

Let's say I have this:
$array = array("john" => "doe", "foe" => "bar", "oh" => "yeah");
foreach($array as $i=>$k)
{
echo $i.'-'.$k.',';
}
echoes "john-doe,foe-bar,oh-yeah,"
How do I get rid of the last comma?
Alternatively you can use the rtrim function as:
$result = '';
foreach($array as $i=>$k) {
$result .= $i.'-'.$k.',';
}
$result = rtrim($result,',');
echo $result;
I dislike all previous recipes.
Php is not C and has higher-level ways to deal with this particular problem.
I will begin from the point where you have an array like this:
$array = array('john-doe', 'foe-bar', 'oh-yeah');
You can build such an array from the initial one using a loop or array_map() function. Note that I'm using single-quoted strings. This is a micro-optimization if you don't have variable names that need to be substituted.
Now you need to generate a CSV string from this array, it can be done like this:
echo implode(',', $array);
One method is by using substr
$array = array("john" => "doe", "foe" => "bar", "oh" => "yeah");
$output = "";
foreach($array as $i=>$k)
{
$output .= $i.'-'.$k.',';
}
$output = substr($output, 0, -1);
echo $output;
Another method would be using implode
$array = array("john" => "doe", "foe" => "bar", "oh" => "yeah");
$output = array();
foreach($array as $i=>$k)
{
$output[] = $i.'-'.$k;
}
echo implode(',', $output);
I don't like this idea of using substr at all, since it's the style of bad programming. The idea is to concatenate all elements and to separate them by special "separating" phrases. The idea to call the substring for that is like to use a laser to shoot the birds.
In the project I am currently dealing with, we try to get rid of bad habits in coding. And this sample is considered one of them. We force programmers to write this code like this:
$first = true;
$result = "";
foreach ($array as $i => $k) {
if (!$first) $result .= ",";
$first = false;
$result .= $i.'-'.$k;
}
echo $result;
The purpose of this code is much clearer, than the one that uses substr. Or you can simply use implode function (our project is in Java, so we had to design our own function for concatenating strings that way). You should use substr function only when you have a real need for that. Here this should be avoided, since it's a sign of bad programming style.
I always use this method:
$result = '';
foreach($array as $i=>$k) {
if(strlen($result) > 0) {
$result .= ","
}
$result .= $i.'-'.$k;
}
echo $result;
try this code after foreach condition then echo $result1
$result1=substr($i, 0, -1);
Assuming the array is an index, this is working for me. I loop $i and test $i against the $key. When the key ends, the commas do not print. Notice the IF has two values to make sure the first value does not have a comma at the very beginning.
foreach($array as $key => $value)
{
$w = $key;
//echo "<br>w: ".$w."<br>";// test text
//echo "x: ".$x."<br>";// test text
if($w == $x && $w != 0 )
{
echo ", ";
}
echo $value;
$x++;
}
this would do:
rtrim ($string, ',')
see this example you can easily understand
$name = ["sumon","karim","akash"];
foreach($name as $key =>$value){
echo $value;
if($key<count($name){
echo ",";
}
}
I have removed comma from last value of aray by using last key of array. Hope this will give you idea.
$last_key = end(array_keys($myArray));
foreach ($myArray as $key => $value ) {
$product_cateogry_details="SELECT * FROM `product_cateogry` WHERE `admin_id`='$admin_id' AND `id` = '$value'";
$product_cateogry_details_query=mysqli_query($con,$product_cateogry_details);
$detail=mysqli_fetch_array($product_cateogry_details_query);
if ($last_key == $key) {
echo $detail['product_cateogry'];
}else{
echo $detail['product_cateogry']." , ";
}
}
$foods = [
'vegetables' => 'brinjal',
'fruits' => 'orange',
'drinks' => 'water'
];
$separateKeys = array_keys($foods);
$countedKeys = count($separateKeys);
for ($i = 0; $i < $countedKeys; $i++) {
if ($i == $countedKeys - 1) {
echo $foods[$separateKeys[$i]] . "";
} else {
echo $foods[$separateKeys[$i]] . ", \n";
}
}
Here $foods is my sample associative array.
I separated the keys of the array to count the keys.
Then by a for loop, I have printed the comma if it is not the last element and removed the comma if it is the last element by $countedKeys-1.

PHP foreach loop

I have the array example below that I am using to dynamically create an SQL query based on the options ticked in a form. The code below tests whether there is a value, if so, append it to the array:
if ($lookchild) { $val[]='lookchild'; }
if ($mentalcap) { $val[]='mentalcap'; }
if ($mentalheal) { $val[]='mentalheal'; }
if ($olderpeople) { $val[]='olderpeople'; }
if ($palcare) { $val[]='palcare'; }
I am then looping through the array and adding the rest of the SQL statement:
foreach ($val as $r){
echo $r.'=1 AND ';
}
This produces:
olderpeople=1 AND palcare=1 AND lookchild=1 AND
When the loop reaches the last entry, I don't want it to append the AND to it as the SQL statement needs to close after that point.
How I want it to complete:
olderpeople=1 AND palcare=1 AND lookchild=1
Implode
In these situations you can use implode
It 'glues' an array together.
implode ( string $glue , array
$pieces )
Example:
echo implode('=1 AND ', $val);
echo '=1';
A common trick is to use 'WHERE 1=1' then you can append ' AND foo = bar' without a syntax error.
WHERE 1=1 AND olderpeople=1 AND palcare=1 AND lookchild=1
This is what implode() is for:
$result = array();
foreach ($val as $r){
$result[] = "$r=1";
}
$result = implode($result, ' AND ');
Live Example
Just don't print the AND for the last value of the foreach loop. Here is the code to use:
foreach ($val as $r){
echo $r.'=1';
if (next($val)) {
echo ' AND ';
}
}
use the implode function
$sql = implode("=1 AND ", $array)."=1";
and you wont have to use a for loop :)
Instead on assigning palcare to $val[], assign $val[] = "palcare = 1" etc. Them
implode(" AND ", $val);
Try this :
$isFirst = true;
foreach ($val as $r){
if(!$isFirst){
echo ' AND ';
}else{
$isFirst = false;
}
echo $r.'=1';
}
I would remove the last 4 characters of the string with:
$r = '';
foreach ($val as $r){
$r.'=1 AND ';
}
$r = substr($r, 0, -4);
echo $r;
Checkout http://ca3.php.net/manual/en/function.substr.php, quick and easy
If you have to do it with a foreach (and for some reason you cant use implode, which is a good suggestion) you will need a way to keep track of where you are.
I thought to add the "AND" before anything but the first item, instead of adding it after anything but the last item, something like this:
$sqlwhere = "";
foreach ($val as $r){
if($sqlwhere ==""){
$sqlwhere = $r;
}
else {
$sqlwhere .= " AND " . $sqlwhere;
}
}
echo $sqlwhere;
I used a varable instead of just echoing it out too, which I find useful in complicated sql statements anyway.
Use implode. But if for some reason you need to loop (such as you need to do more logic than just joining the strings), use a separator approach:
$seperator = '';
$result = '';
foreach ($array as $value) {
// .. Do stuff here
$result .= $seperator . $value;
$seperator = ' AND ';
}
The benefit is both brevity and flexibility without checking conditions all the time...
Since you are using an array, you can also use count to figure out how many are in the array and if you are on the last item, don't append the 'AND'.
$result = array();
$totalcount = count($val);
$currentCount = 0;
foreach ($val as $r){
$currentCount ++;
if ($currentCount != $totalcount){$result[] = "$r=1 AND ";}else{$result[] = "$r=1";}
}

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