Featured post

c# - Usage of Server Side Controls in MVC Frame work -

-
i using asp.net 4.0 , mvc 2.0 web application. project requiremrnt have use server side control in application not possibl in noraml case. ideally want use adrotator control , datalist control. i saw few samples , references in codepleax mvc controllib howwver found less useful. can tell how utilize theese controls in asp.net application along mvc. note: please provide functionalities related adrotator , datalist controls not equivalent functionalities thanks in advace. mvc pages not use normal .net solution makes use of normal .net components impossible. a normal .net page use event driven solution call different methods service side mvc use actions , view completly different way handle things. also, mvc not use viewstate normal .net controlls require. found article discussing mixing of normal .net , mvc.
3 comments

What is the idiomatic way to assoc several keys/values in a nested map in Clojure? -

-

imagine have map this:

(def person {   :name {     :first-name "john"     :middle-name "michael"     :last-name "smith" }})

what idiomatic way change values associated both :first-name , :last-name in 1 expression?

(clarification: let's want set :first-name "bob" , :last-name "doe". let's map has other values in want preserve, constructing scratch not option)

here couple of ways.

user> (update-in person [:name] assoc :first-name "bob" :last-name "doe") {:name {:middle-name "michael", :last-name "doe", :first-name "bob"}}  user> (update-in person [:name] merge {:first-name "bob" :last-name "doe"}) {:name {:middle-name "michael", :last-name "doe", :first-name "bob"}}  user> (update-in person [:name] {:first-name "bob" :last-name "doe"}) {:name {:middle-name "michael", :last-name "doe", :first-name "bob"}}  user> (-> person            (assoc-in [:name :first-name] "bob")           (assoc-in [:name :last-name]  "doe")) {:name {:middle-name "michael", :last-name "doe", :first-name "bob"}}

edit

update-in recursive assocs on map. in case it's equivalent to:

user> (assoc person :name               (assoc (:name person)                      :first-name "bob"                      :last-name "doe"))

the repetition of keys becomes more , more tedious go deeper series of nested maps. update-in's recursion lets avoid repeating keys (e.g. :name) on , over; intermediary results stored on stack between recursive calls. take @ source update-in see how it's done.

user> (def foo {:bar {:baz {:quux 123}}}) #'user/foo  user> (assoc foo :bar               (assoc (:bar foo) :baz                      (assoc (:baz (:bar foo)) :quux                             (inc (:quux (:baz (:bar foo))))))) {:bar {:baz {:quux 124}}}  user> (update-in foo [:bar :baz :quux] inc) {:bar {:baz {:quux 124}}}

assoc dynamic (as update-in, assoc-in, , other clojure functions operate on clojure data structures). if assoc onto map, returns map. if assoc onto vector, returns vector. @ source assoc , take in in rt.java in clojure source details.


Comments

Post a Comment

Popular posts from this blog

c# - Usage of Server Side Controls in MVC Frame work -

-
i using asp.net 4.0 , mvc 2.0 web application. project requiremrnt have use server side control in application not possibl in noraml case. ideally want use adrotator control , datalist control. i saw few samples , references in codepleax mvc controllib howwver found less useful. can tell how utilize theese controls in asp.net application along mvc. note: please provide functionalities related adrotator , datalist controls not equivalent functionalities thanks in advace. mvc pages not use normal .net solution makes use of normal .net components impossible. a normal .net page use event driven solution call different methods service side mvc use actions , view completly different way handle things. also, mvc not use viewstate normal .net controlls require. found article discussing mixing of normal .net , mvc.
Read more

ios - Very simple iPhone App crashes on UILabel settext -

-
i have simple application. have button , label in ib. have ibaction onclick calls settext on label. there's outlet label. connected in ib. crashes app first time in simulator. when launch again, sets text. crashes again next time. crashes on actual device. should simple, i'm not sure i'm doing wrong. thanks. in .h file : #import <uikit/uikit.h> @interface untitledviewcontroller : uiviewcontroller { iboutlet uilabel *label; iboutlet uibutton *button; } @property (nonatomic, retain) uilabel *label; -(ibaction) onclick1: (id) sender; @end and in .m: - (ibaction) onclick1: (id) sender { //[label settext:@"hello world!"]; label.text = @"hello world!"; //[button settitle:@"clicked" forstate:uicontrolstatenormal]; } sorry, i'm new site. how crash log , stack? thanks. edit : while answer technically correct, doesn't answer question @ :( sorry < warning - guess > if you're...
Read more

mysql - Why there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT clause? -

-
why there can 1 timestamp column current_timestamp in default or on update clause? create table `foo` ( `productid` int(10) unsigned not null, `addeddate` timestamp not null default current_timestamp, `updateddate` timestamp not null default current_timestamp on update current_timestamp ) engine=innodb; the error results: error code : 1293 incorrect table definition; there can 1 timestamp column current_timestamp in default or on update clause this limitation, due historical, code legacy reasons, has been lifted in recent versions of mysql: changes in mysql 5.6.5 (2012-04-10, milestone 8) previously, @ 1 timestamp column per table automatically initialized or updated current date , time. restriction has been lifted. timestamp column definition can have combination of default current_timestamp , on update current_timestamp clauses. in addition, these clauses can used datetime column definitions. more information, see automati...
Read more