Re: alter a map in a vector (reference)
Hello,
A note about the code organization : I think you should strive to
separate the code that does side effects from the code that works on
the datastructures.
This means you could refactor your refactored version as such:
=> (def example
(ref
[{:id 1 :email {"a...@mail.com" 1}}
{:id 2 :email {"d...@mail.com" 1}}
{:id 3 :email {"g...@mail.com" 2}}
{:id 4 :email {"f...@mail.com" 2}}]))
(defn update-counter-val [v id]
(let [at-after (drop-while #(not= id (:id %)) v)
mod-key (-> at-after first :email keys first)
location (- (count v) (count at-after))]
(update-in v [location :email mod-key] inc)))
(defn update-counter [id xs]
(dosync (alter xs update-counter-val id)))
(dotimes [_ 3]
(update-counter 3 example))
@example
#'user/example
#'user/update-counter-val
#'user/update-counter
nil
[{:email {"a...@mail.com" 1}, :id 1} {:email {"d...@mail.com" 1}, :id
2} {:email {"g...@mail.com" 5}, :id 3} {:email {"f...@mail.com" 2},
:id 4}]
Finally, you could save you some pain if you had a representation of
the data that is more amenable to manipulation.
Depending on your requirements:
- do you really need a vector, or can you go with a set ?
e.g. change example to
(def example
(ref
#{{:id 1 :email {"a...@mail.com" 1}}
{:id 2 :email {"d...@mail.com" 1}}
{:id 3 :email {"g...@mail.com" 2}}
{:id 4 :email {"f...@mail.com" 2}}}))
This way, you can simplify the manipulation by using clojure.set :
=> (require '[clojure.set :as s])
(def example
(ref
#{{:id 1 :email {"a...@mail.com" 1}}
{:id 2 :email {"d...@mail.com" 1}}
{:id 3 :email {"g...@mail.com" 2}}
{:id 4 :email {"f...@mail.com" 2}}}))
(defn update-counter-val [v id]
(let [r (first (s/select #(= id (:id %)) v))
mod-key (-> r :email keys first)]
(-> v (disj r) (conj (update-in r [:email mod-key] inc)
(defn update-counter [id xs]
(dosync (alter xs update-counter-val id)))
(dotimes [_ 3]
(update-counter 3 example))
@example
nil
#'user/example
#'user/update-counter-val
#'user/update-counter
nil
#{{:email {"a...@mail.com" 1}, :id 1} {:email {"f...@mail.com" 2}, :id
4} {:email {"g...@mail.com" 5}, :id 3} {:email {"d...@mail.com" 1},
:id 2}}
Or alternatively, you can have the records indexed in a hashmap:
=> (require '[clojure.set :as s])
(def example
(ref
{1 {:id 1 :email {"a...@mail.com" 1}}
2 {:id 2 :email {"d...@mail.com" 1}}
3 {:id 3 :email {"g...@mail.com" 2}}
4 {:id 4 :email {"f...@mail.com" 2}}}))
(defn update-counter-val [v id]
(let [mod-key (-> id v :email keys first)]
(update-in v [id :email mod-key] inc)))
(defn update-counter [id xs]
(dosync (alter xs update-counter-val id)))
(dotimes [_ 3]
(update-counter 3 example))
@example
nil
#'user/example
#'user/update-counter-val
#'user/update-counter
nil
{1 {:email {"a...@mail.com" 1}, :id 1}, 2 {:email {"d...@mail.com" 1},
:id 2}, 3 {:email {"g...@mail.com" 5}, :id 3}, 4 {:email
{"f...@mail.com" 2}, :id 4}}
Also, restructuring the record a little bit could help, but I don't
understand what it's about, so I don't know what to suggest.
Anyway, you could get rid of computing mod-key by leveraging some more
core clojure functions:
(require '[clojure.set :as s])
(def example
(ref
{1 {:id 1 :email {"a...@mail.com" 1}}
2 {:id 2 :email {"d...@mail.com" 1}}
3 {:id 3 :email {"g...@mail.com" 2}}
4 {:id 4 :email {"f...@mail.com" 2}}}))
(defn update-counter-val [v id]
(letfn [(inc-email [m k v] (assoc m k (inc v)))]
(update-in v [id :email] #(reduce-kv inc-email {} %
(defn update-counter [id xs]
(dosync (alter xs update-counter-val id)))
(dotimes [_ 3]
(update-counter 3 example))
@example
(note : this example is a little bit more general: it increments each
value of each email found in the map under the :email key)
finally, if there is only one email per record, then maybe the
structure of the record should be simplified (and the resulting code)
as such:
=> (require '[clojure.set :as s])
(def example
(ref
{1 {:id 1 :email "a...@mail.com" :email-occurences 1}
2 {:id 2 :email "d...@mail.com" :email-occurences 1}
3 {:id 3 :email "g...@mail.com" :email-occurences 2}
4 {:id 4 :email "f...@mail.com" :email-occurences 2}}))
(defn update-counter-val [v id]
(update-in v [id :email-occurences] inc))
(defn update-counter [id xs]
(dosync (alter xs update-counter-val id)))
(dotimes [_ 3]
(update-counter 3 example))
@example
nil
#'user/example
#'user/update-counter-val
#'user/update-counter
nil
{1 {:email-occurences 1, :email "a...@mail.com", :id 1}, 2
{:email-occurences 1, :email "d...@mail.com", :id 2}, 3
{:email-occurences 5, :email "g...@mail.com", :id 3}, 4
{:email-occurences 2, :email "f...@mail.com", :id 4}}
At this point, it
Re: alter a map in a vector (reference)
Here's the refactored version.user> (def example
(ref
[{:id 1 :email {"a...@mail.com" 1}}
{:id 2 :email {"d...@mail.com" 1}}
{:id 3 :email {"g...@mail.com" 2}}
{:id 4 :email {"f...@mail.com" 2}}]))
#'user/example
user>
(defn update-counter [id xs]
(dosync
(let [_ @xs
at-after (drop-while #(not= id (:id %)) _)
mod-key (-> at-after first :email keys first)
location (- (count _) (count at-after))]
(alter xs update-in [location :email mod-key] inc
#'user/update-counter
user> (dotimes [_ 3]
(update-counter 3 example))
nil
user> (clojure.pprint/pprint @example)
[{:email {"a...@mail.com" 1}, :id 1}
{:email {"d...@mail.com" 1}, :id 2}
{:email {"g...@mail.com" 5}, :id 3}
{:email {"f...@mail.com" 2}, :id 4}]
nil
12.06.2013, 14:47, "Meikel Brandmeyer (kotarak)" :Hi,Am Mittwoch, 12. Juni 2013 06:39:59 UTC+2 schrieb Kelker Ryan:user> (defn update-counter [id xs](let [at-after (drop-while #(not= id (:id %)) @xs)
to-modify (-> at-after first :email)
mod-key (-> to-modify keys first)
location (let [_ (- (count @xs) (count at-after))]
(if-not (pos? _) 0 _))]
(dosync
(alter xs update-in [location :email mod-key] inc
You have to wrap all accesses to xs in the same dosync. Kind regardsMeikel
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Re: alter a map in a vector (reference)
Hi, Am Mittwoch, 12. Juni 2013 06:39:59 UTC+2 schrieb Kelker Ryan: > > user> (defn update-counter [id xs] > > (let [at-after (drop-while #(not= id (:id %)) @xs) > to-modify (-> at-after first :email) > mod-key (-> to-modify keys first) > location (let [_ (- (count @xs) (count at-after))] > (if-not (pos? _) 0 _))] > (dosync >(alter xs update-in [location :email mod-key] inc > > You have to wrap all accesses to xs in the same dosync. Kind regards Meikel -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: alter a map in a vector (reference)
I've seen some interesting responses, but here's my solution. user> (def example
(ref
[{:id 1 :email {"a...@mail.com" 1}}
{:id 2 :email {"d...@mail.com" 1}}
{:id 3 :email {"g...@mail.com" 2}}
{:id 4 :email {"f...@mail.com" 2}}]))
#'user/example
user> (defn update-counter [id xs]
(let [at-after (drop-while #(not= id (:id %)) @xs)
to-modify (-> at-after first :email)
mod-key (-> to-modify keys first)
location (let [_ (- (count @xs) (count at-after))]
(if-not (pos? _) 0 _))]
(dosync
(alter xs update-in [location :email mod-key] inc
#'user/update-counter
user> (update-counter 4 example)
-- output removed --
user> (update-counter 1 example)
-- output removed --
user> (clojure.pprint/pprint @example)
[{:email {"a...@mail.com" 2}, :id 1}
{:email {"d...@mail.com" 1}, :id 2}
{:email {"g...@mail.com" 2}, :id 3}
{:email {"f...@mail.com" 3}, :id 4}]
nil
12.06.2013, 11:19, "Yoshinori Kohyama" : > Solutions seem to depend on whether you have two or more mail addresses in a ':emails' section or not.> If you have, you should identify the mail address of which you want to increment the value.> Anyway, try below:>> (dosync> (alter result> (fn [v]> (mapv second> (update-in (into {} (map #(vector (:id %) %) v))> [1 :emails "a...@mail.com"]> inc)>> HTH,> with regards,> Yoshinori Kohyama>> --> --> You received this message because you are subscribed to the Google> Groups "Clojure" group.> To post to this group, send email to clojure@googlegroups.com> Note that posts from new members are moderated - please be patient with your first post.> To unsubscribe from this group, send email to> clojure+unsubscr...@googlegroups.com> For more options, visit this group at> http://groups.google.com/group/clojure?hl=en> ---> You received this message because you are subscribed to the Google Groups "Clojure" group.> To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com.> For more options, visit https://groups.google.com/groups/opt_out.
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Re: alter a map in a vector (reference)
Solutions seem to depend on whether you have two or more mail addresses in
a ':emails' section or not.
If you have, you should identify the mail address of which you want to
increment the value.
Anyway, try below:
(dosync
(alter result
(fn [v]
(mapv second
(update-in (into {} (map #(vector (:id %) %) v))
[1 :emails "a...@mail.com"]
inc)
HTH,
with regards,
Yoshinori Kohyama
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Re: alter a map in a vector (reference)
You *can* update this inside the vector, but if you want to key by :id, I
would personally recommend, you put the email data into a map and look it
up by :id, like this:
{1 {:id 1 :email {"a...@mail.com 1}}
2 {:id 2 :email {"d...@mail.com 1}}
3 {:id 3 :email {"g...@mail.com 2}}}
Best,
Alex
On Mon, Jun 3, 2013 at 1:44 PM, Yinka Erinle wrote:
> Thanks Meikel for the prompt reply, that does it.
>
> Please can you elaborate on how I can use the solution below to update a
> particular entry in the vector.
>
> [{:id 1 :email {"a...@mail.com 1}}
> {:id 2 :email {"d...@mail.com 1}}
> {:id 3 :email {"g...@mail.com 2}}]
>
> So I will like to write a function that accepts an id and then updates the
> counter in email section of the given id.
>
> (defn update-counter [x xs]
>(dosync
> (alter result ..
>
> Thanks again for your time.
>
>
> On Monday, June 3, 2013 9:23:47 PM UTC+1, Meikel Brandmeyer (kotarak)
> wrote:
>>
>> Hi,
>>
>> Am Montag, 3. Juni 2013 22:16:54 UTC+2 schrieb Yinka Erinle:
>>>
>>> Given I have the following
>>> (def result (ref [ { :id 1 :emails { "yi...@mail.com" 1}} ] ) )
>>>
>>> I like to alter the result in a transaction to become
>>> [{:id 1 :emails { "yi...@mail.com" 2}}]; increment the counter from
>>> 1 to 2
>>>
>>> Please can someone provide pointers.
>>>
>>>
>> You can use the uniform update principle to stitch together alter and
>> update-in.
>>
>> (dosync
>> (alter result update-in [0 :emails "a@b.c"] inc))
>>
>> Kind regards
>> Meikel
>>
>>
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Re: alter a map in a vector (reference)
Thanks Meikel for the prompt reply, that does it.
Please can you elaborate on how I can use the solution below to update a
particular entry in the vector.
[{:id 1 :email {"a...@mail.com 1}}
{:id 2 :email {"d...@mail.com 1}}
{:id 3 :email {"g...@mail.com 2}}]
So I will like to write a function that accepts an id and then updates the
counter in email section of the given id.
(defn update-counter [x xs]
(dosync
(alter result ..
Thanks again for your time.
On Monday, June 3, 2013 9:23:47 PM UTC+1, Meikel Brandmeyer (kotarak) wrote:
>
> Hi,
>
> Am Montag, 3. Juni 2013 22:16:54 UTC+2 schrieb Yinka Erinle:
>>
>> Given I have the following
>> (def result (ref [ { :id 1 :emails { "yi...@mail.com" 1}} ] ) )
>>
>> I like to alter the result in a transaction to become
>> [{:id 1 :emails { "yi...@mail.com" 2}}]; increment the counter from
>> 1 to 2
>>
>> Please can someone provide pointers.
>>
>>
> You can use the uniform update principle to stitch together alter and
> update-in.
>
> (dosync
> (alter result update-in [0 :emails "a@b.c"] inc))
>
> Kind regards
> Meikel
>
>
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Re: alter a map in a vector (reference)
Hi,
Am Montag, 3. Juni 2013 22:16:54 UTC+2 schrieb Yinka Erinle:
>
> Given I have the following
> (def result (ref [ { :id 1 :emails { "yi...@mail.com " 1}} ]
> ) )
>
> I like to alter the result in a transaction to become
> [{:id 1 :emails { "yi...@mail.com " 2}}]; increment the
> counter from 1 to 2
>
> Please can someone provide pointers.
>
>
You can use the uniform update principle to stitch together alter and
update-in.
(dosync
(alter result update-in [0 :emails "a@b.c"] inc))
Kind regards
Meikel
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alter a map in a vector (reference)
Hi,
I struggling to find a way to alter a value in a map that resides in a
vector.
Given I have the following
(def result (ref [ { :id 1 :emails { "yi...@mail.com" 1}} ] ) )
I like to alter the result in a transaction to become
[{:id 1 :emails { "yi...@mail.com" 2}}]; increment the counter from 1
to 2
Please can someone provide pointers.
Thanks,
Yinka.
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