SimonB86

  var filteredCustomers = customers
      .Join(orders,
          c => c.customerid,
          o => o.customerid,
          (c, o) => new { Customer = c, Order = o }
      )
      .Where(x => x.Customer.IsMale && x.Customer.Age > 30)
      .Where(x => x.Order.IsPending);

  var x = from post in posts
          let keywords = post.split(' ')
          ...

  var x = posts
          .Select(post => new { keywords = post.split(' '), post })
          ...