PHP array not extracting as expected - why is this? - php

Question

When using an array in a foreach loop
$stdlist = rtrim(trim($_POST['stdlist'], '/'), '/');
$stdlist = explode('/' , $stdlist);
print_r($stdlist);
foreach($stdlist as $value)
{
echo "<br>";
echo $_POST[$value];
}
the array $stdlist is clearly working; when printed this returns:
Array ( [0] => 1 [1] => 6 [2] => 7 [3] => 8 )
My problem is that when I use the foreach loop to extract out of the array one value at a time, the following gets printed to the page:
4
4
Notice: Undefined offset: 7 in C:\Program Files\wamp\www...on line 35
Notice: Undefined offset: 7 in C:\Program Files\wamp\www...on line 35
I know this isn't functioning as intended as I am expecting the following:
1
6
7
8
Could somebody please explain why this is happening and how to fix this issue? Thanks :-)

Answer 1

You have to print the $value bacause $value have original array value not index.
And you are getting array in $stdlist from exploding this post variable $_POST['stdlist'].
foreach($stdlist as $value)
{
echo "<br>";
echo $value;
}
Now you will get your required result.

Answer 2

instead of using echo $_POST[$value]; just use echo $value when you use foreach loop for an array, the values on each nodes are automatically extracted.
foreach ($array as $index=>$value){
echo "index is $index and value associated with it is $value.";
}
Hope this helps.

Answer 3

foreach($stdlist as $value)
{
echo "<br>";
echo $value;
}
when you use foreach the $value is not the position in the array, if you want to use the position you need to do
for($pos=0; $pos<sizeof($stdlist); $pos++)
{
echo "<br>";
echo $stdlist[$pos];
}

Answer 4

When using the foreach() loop, I'd recommend assigning both the position and value to their own respective variables and then print them to the screen to see how the foreach loop has assigned the values.
foreach( $stdlist as $position => $value ) {
echo "The current position is $position, and the value of \$stdlist[$position] is
$value";
}