Regular expression to get the value from array - php

Question

I need to get the value for a certain key, they key is not the same all the time.
initial part remains same but every time I get new id added in the end.
My array is like this:
senario 1:
Array
(
[custom_194_1] => 123
[_f_upload] => Save
)
senario 2:
Array
(
[custom_194_2] => 456
[_f_upload] => Save
)
I need to get the value 123 in senario 1, 456 in senario 2.
Can anyone please help me on how to get the value from this array key.

Answer 1

If your key is always the first element, and the array is $array the fastest way is:
$result = reset($array);
Or if you don't want to mess with the array's internal pointer:
$result = array_values($array)[0];
If you want the value of the key:
$key = array_keys($array)[0];

Answer 2

Thanks for your time guys. I'm using foreach to loop through and then checking with every key with substring. Hope it helps someone in future, not the very best solution though.
foreach($fields as $key => $val)
{
if(substr($key,0,10)=='custom_194'){
$realValue = $val;
echo "<br>value i'm looking for:";print_r($val);
}
}

Answer 3

Because you stated that you want the number at the end of the key and because you appear to want to learn more about regular expressions... This is not a hard task to do with preg_match.
Assume $array is the array that you begin with that has all the key=>val values.
foreach($fields as $key=>$val)
{
if(preg_match('/^custom_194_([0-9]+)$/', $key, $matches))
{
$num = $matches[1];
print "Key number $num has value $val\n";
}
}
The regular expression is ^custom_194_([0-9]+)$. The ^ means "beginning of the string." The $ means "end of the string." You can see that we explicitly spell out custom_194_. Then, we use ( and ) to identify a substring that we want to keep in the matches array. Inside ( and ), we look for the characters 0 through 9 using [0-9]. The + means "1 or more characters." So, we want 1 or more 0 through 9 characters.
The match array contains the entire string matched in the first index and then each sub-match in the remaining indexes. We only have one sub-match, which will be in index 1. So, $num is in $matches[1].