Check if a certain value exists within an array

Question

Colleagues,

we have a menu with 11 items and each item will open a page containing their respective PDF files. To avoid creating 11 different pages, we just create a page called pdf.php and put it in the links in this menu as follows:

<a href='?pag=1'>Orçamentário</a>
<a href='?pag=2'>Dados</a>
<a href='?pag=3'>Contas</a>

Up to link number 11 and we are rescuing within the same page that contains the menu in this way:

<?php if(isset($_REQUEST['pag'])){ include("pdf.php?pag=".$_REQUEST['pag']);} ?>

However, this will generate a querystring in the browser. Ex.: www.site.com.br? pag=1. So to prevent the user from typing the numbering directly into the wrong browser. Ex.: www.site.com.br? pag=12, we would like a message to appear to him Select an item from the menu.

To avoid giving an if() or switch() 11 times, we thought of creating an array with fixed values from 0 to 11 and if these values did not exist, the message would appear.

How could we do that? We thought about using in_array, but we couldn’t. See:

$array = array("0","1","2","3");

if(in_array(array(), $array)){
    echo "ok";
}else{
    echo "ops";
}

Answer 1

Despite being a duplicated issue by the requested content, the error is specific to the way you are mounting your if, which should be as follows:

$array = array("0","1","2","3");

if(in_array($_GET['pag'], $array)){
    echo "ok";
}else{
    echo "ops";
}