title: loop into array and get only specific key value pair
body: <p>I have this $_POST array coming from a paypal transaction</p>
  
  <pre><code>Array
  (
      [address_city] =&gt; San Jose
      [address_country] =&gt; United States
      [address_country_code] =&gt; US
      [address_name] =&gt; Test User
      [address_state] =&gt; CA
      [address_status] =&gt; confirmed
      [address_street] =&gt; 1 Main St
      [address_zip] =&gt; 95131
      [business] =&gt; test1_biz@gmail.com
      [charset] =&gt; windows-1252
      [custom] =&gt; 
      [first_name] =&gt; Test
      [item_name1] =&gt; Product Name 1
      [item_name2] =&gt; Product Name 6
      [item_name3] =&gt; Product Name 8
      [item_number1] =&gt; 1
      [item_number2] =&gt; 6
      [item_number3] =&gt; 8
      [last_name] =&gt; User
      [mc_currency] =&gt; USD
      [mc_fee] =&gt; 0.82
      [mc_gross] =&gt; 18.00
      [mc_gross_1] =&gt; 14.00
      [mc_gross_2] =&gt; 2.00
      [mc_gross_3] =&gt; 2.00
      [mc_handling] =&gt; 0.00
      [mc_handling1] =&gt; 0.00
      [mc_handling2] =&gt; 0.00
      [mc_handling3] =&gt; 0.00
      [mc_shipping] =&gt; 11.00
      [mc_shipping1] =&gt; 11.00
      [mc_shipping2] =&gt; 0.00
      [mc_shipping3] =&gt; 0.00
      [notify_version] =&gt; 3.4
      [num_cart_items] =&gt; 3
      [payer_email] =&gt; test_biz@gmail.com
      [payer_id] =&gt; TRCLJTHLNCJ7Q
      [payer_status] =&gt; verified
      [payment_date] =&gt; 22:52:56 Jan 27, 2012 PST
      [payment_fee] =&gt; 0.82
      [payment_gross] =&gt; 18.00
      [payment_status] =&gt; Completed
      [payment_type] =&gt; instant
      [protection_eligibility] =&gt; Eligible
      [quantity1] =&gt; 1
      [quantity2] =&gt; 1
      [quantity3] =&gt; 1
      [receiver_email] =&gt; test_biz@gmail.com
      [receiver_id] =&gt; 74PV23B8KSK84
      [residence_country] =&gt; US
      [tax] =&gt; 0.00
      [tax1] =&gt; 0.00
      [tax2] =&gt; 0.00
      [tax3] =&gt; 0.00
      [test_ipn] =&gt; 1
      [transaction_subject] =&gt; Shopping CartProduct Name 1Product Name 6Product Name 8
      [txn_id] =&gt; 7BS85664SB906284D
      [txn_type] =&gt; cart
      [verify_sign] =&gt; AJ2IuqHp8G0lIxhedAqrwRQbv8fVA4-Gum9e7DMZmEWIFrljEwFCJDfP
  )
  1
  </code></pre>
  
  <p>as you can see, there are key value pairs like this,</p>
  
  <pre><code>[items_name1] =&gt; Product Name 1
  [items_name2] =&gt; Product Name 2
  [items_name3] =&gt; Product Name 3
  </code></pre>
  
  <p>those keys aren't constant, I mean, it came from a shopping cart, so the item name depends on how many items were placed in the shopping cart to be purchased.. now my question is,
      How to loop to that post array, and get only the item_names plus their corresponding values ?, because I need them and save in a db table</p>