Hi, Ray.
When you are doing things that have a relational algebra feel to them
(joins, etc.), you might want to consider the fns in the clojure.set
namespace. E.g.:
;; convert vectors of records to sets, then:
> (clojure.set/join
(clojure.set/rename items {:id :iid :name :iname}) ; to p
Hilarious - I am so conditioned already to have everything in a list :)
Thanks for your patient explanation. Merry xmas.
ray
Ray
On Sunday 16 December 2012 at 22:20, Benjamin R. Haskell wrote:
> On Sun, 16 Dec 2012, mond wrote:
>
> > One small thing Ben... when I try to use the final formu
On Sun, 16 Dec 2012, mond wrote:
One small thing Ben... when I try to use the final formulation I receive an
error:
(def joined-products (map product-with-item products))
user=> (joined-products)
ClassCastException clojure.lang.LazySeq cannot be cast to clojure.lang.IFn
user/eval241 (NO_SOUR
One small thing Ben... when I try to use the final formulation I receive an
error:
(def joined-products (map product-with-item products))
user=> (joined-products)
ClassCastException clojure.lang.LazySeq cannot be cast to clojure.lang.IFn
user/eval241 (NO_SOURCE_FILE:9)
Any ideas?
Thanks in a
Great stuff Ben. Thanks.
ray
On Saturday, December 15, 2012 10:54:42 PM UTC+1, Benjamin R. Haskell wrote:
>
> On Sat, 15 Dec 2012, mond wrote:
>
> > Thanks for picking up the cudgels Ben!
>
> Ha. It's nice to have reached a point where I feel at-all confident
> with any of this... happy to he
On Sat, 15 Dec 2012, mond wrote:
Thanks for picking up the cudgels Ben!
Ha. It's nice to have reached a point where I feel at-all confident
with any of this... happy to help.
To be honest I am struggling to repeat your advice in the REPL. In
any case, I decided to change the data struct
Thanks for picking up the cudgels Ben!
To be honest I am struggling to repeat your advice in the REPL. In any
case, I decided to change the data structures in line with your advice and
put the IDs into maps rather than the records.
(defrecord Item [name product quantity purchased])
(defrecord
(responses inline)
On Sat, 15 Dec 2012, mond wrote:
I have defined these types of records for modelling a simple shopping cart:
; An item in the cart
(defrecord Item [id name product quantity purchased])
; The product that relates to the item in the cart
(defrecord Product [id name descriptio
On Sat, 15 Dec 2012, Benjamin R. Haskell wrote:
Or if you really want a list, you need to quote it:
(map (fn [item product] '(:id item :description product)) items products)
Oops, wrong. Rather, you would want clojure.core/list:
(map (fn [item product] (list :id item :description product))
OK - I have it now:
(map (fn [item product] (= (:product item (:id product))) [(:id item)
(:description product)]) items products)
This feels OK to me but if anyone has a nicer / more idiomatic solution, I
will be happy to take feedback.
ray
On Saturday, December 15, 2012 7:08:21 PM UTC+1, mo
I think I am close to answering this myself (which is always nice!)
I have done the necessary joins with map and I can return a product
description
user=> (map (fn [item product] (= (:product item (:id product)))
(:description product)) items products)
("Men's Leather Slip on Brogues" "CK Y Fro
11 matches
Mail list logo
