substr前两个字母匹配数组不起作用

Question

I have a string which is being generated from an input field and i want to check the first two characters and see if they are found in an array. If they are I want a message to appear.

Can anyone explain why this isn't working please?

$i = strtoupper($_POST['postcode']);
    $ep = array("AB", "BT", "GY", "HS", "IM", "IV", "JE", "PH", "KW");

    if (isset($i)) {

    if(substr($i, 0, 2) === in_array($i, $ep)) {
        echo "Sorry we don't deliver to your postcode";
    }   
}

Answer 1

Your usage of in_array is wrong. Change

if(substr($i, 0, 2) === in_array($i, $ep)) {
  echo "Sorry we don't deliver to your postcode";
}   

to

if(in_array(substr($i, 0, 2), $ep)) {
  echo "Sorry we don't deliver to your postcode";
}   

Answer 2

You misunderstand how in_array works, check the manual for more details.

The following code is an improved way to check if the given post code is valid

<?php
/**
 * Check if the given post code is valid
 * @param string $postcode 
 * @return boolean
 */
function is_valid_postcode( $postcode = '' )
{
    $ep = array("AB", "BT", "GY", "HS", "IM", "IV", "JE", "PH", "KW");
    $postcode = strtoupper( $postcode );
    return in_array( $postcode , $ep );
}

if( isset( $_POST['postcode'] ) ){

    // Remove unwanted spaces if they're there
    $postcode = trim( $_POST['postcode'] );

    // Extract only the first two caracters
    $postcode = substr($postcode, 0, 2 );

    // Check if the submitted post code is valid
    if( !is_valid_postcode( $postcode ) ){
        echo "Sorry we don't deliver to your postcode";
    }
}

Answer 3

Use it like this:

$i = strtoupper($_POST['postcode']);
$ep = array("AB", "BT", "GY", "HS", "IM", "IV", "JE", "PH", "KW");

if (isset($i)) {

    $i = substr($i, 0, 2);

    if(in_array($i, $ep)) {
        echo "Sorry we don't deliver to your postcode";
    }   
}

Answer 4

Try this:

if(in_array(substr($i, 0, 2), $ep)) {
    echo "Sorry we don't deliver to your postcode";
}  

Answer 5

Try it like this:

$i = strtoupper($_POST['postcode']);
    $ep = array("AB", "BT", "GY", "HS", "IM", "IV", "JE", "PH", "KW");

    if (isset($i)) {
    $i = substr($i, 0, 2);
    if(in_array($i, $ep)) {
        echo "Sorry we don't deliver to your postcode";
    }   
}