Used a better example

components/cache/introduction.rst

@@ -55,20 +55,20 @@ and define the namespace used to store the items as the first argument::
 Now you can create, retrieve, updated and delete items using this cache pool::
 
  // create a new item by trying to get it from the cache
- $item = $cache->getItem('user_id');
+ $numProducts = $cache->getItem('stats.num_products');
 
  // assign a value to the item and save it
- $item->set('4711');
- $cache->save($item);
+ $numProducts->set('4711');
+ $cache->save($numProducts);
 
- // retrieve the cached item
- $cachedUser = $cache->getItem('user_id');
+ // retrieve the cache item
+ $cachedNumProducts = $cache->getItem('stats.num_products');
  // check whether the item exists in the cache
- $isCached = $cachedUser->isHit();
+ $isCached = $cachedNumProducts->isHit();
  // retrieve the value stored by the item
- $userId = $cachedUser->get();
+ $numProducts = $cachedNumProducts->get();
 
  // remove the cache item
- $cache->deleteItem('user_id');
+ $cache->deleteItem('stats.num_products');
 
 .. _`PSR-6`: http://www.php-fig.org/psr/psr-6/