Hi guys, i have 2 questions that i hope someone will help me on. Because its killing me, i can't solve it.


1) Write a function that will convert an array of lower case strings passed by reference into an array of upper case strings

e.g function convert(&$array_strings){
//insert code
}

I tried this:
function convert(&$array_strings)
{
$array_strings="hello this is php coding in lower case to upper case";
$higher=strtoupper($array_strings);
print("$higher");
}


2)Using regular expressions generate a function that will check if a filename stored in a string is of the correct format. The function should return a Boolean result. Any 1 upper case letter, followed by 3 lowercase letters, followed by any digit, followed by a .php or .PHP file
eg. Gone8.php

I tried this:
function regular_expressions($boolean)
{
if(preg_match("/[A-Z]{1}[a-z]{3}[0-9][.]p[Hh]p/","Gone8.php"))
{
return 1;
if ($boolean == 1)
{
print("true<br/>");
}
return false;
}


Extra: what happens if you try "Gone8.phpProblem" Does it return true or false ? Can you fix the problem if there is one?" --->Can anyone explain the answer and rationale behind it to me ?

Many thanks!

If you want to call your array by reference and convert it to uppercase then you can do this

PHP Code:


//Set array
$arr = Array("bill", "bob", "joan");

//then call the function
convert($arr);

//output will be
//BILL
//BOB
//JOAN


//define function
function convert(&$array_data){
  foreach($array_data as $data){
    $higher = strtoupper($data);
    echo($higher);
  }
} 


that should work for what your trying to do. It will convert an array of strings by reference to uppercase. PHP does not do C style references if that is what you are looking for.

How about using array_walk to apply function to each element of array. Is passed by reference not by value.

PHP Code:

<?php
$fruits = array("lemon","orange","banana","apple");

function upper_case(&$item1)
{
    $item1 = strtoupper("$item1");
}



array_walk($fruits, 'upper_case');

print_r($fruits);// Array (     [0] => LEMON     [1] => ORANGE     [2] => BANANA     [3] => APPLE )

?>

Edited to add Blackthoughts does not pass by reference. $arr remains lowercase

print_r($arr); // Array ( [0] => bill [1] => bob [2] => joan )

the way I did it does pass by reference but when you use strtoupper it creates a new string instead of changing the original. If you want to change the original then maxxximus way is what you want to go with.

edited: If you want to change by reference and change the original array without calling an extra function then you can use this way.

PHP Code:

//Set array
$arr = Array("bob", "bill", "jane");

//then call the function
convert($arr);


print_r($arr);
//output will be
//Array ( [0] => BOB [1] => BILL [2] => JANE ) 


//define function
function convert(&$array_data){
  foreach($array_data as &$data){
    $data = strtoupper($data);
  }
}