In Clojure, how do I sort a set of maps by a key within a value? -


this awkward question phrase, have set of maps so:

(def person-1 {:name "joshua" :birthday {:day 5 :month 12 :year 1960}}) (def person-2 {:name "louise" :birthday {:day 17 :month 4 :year 1987}}) (def person-3 {:name "jessica" :birthday {:day 28 :month 5 :year 1972}})  (def people #{person-1 person-2 person-3})

how sort people birth month, example?

i know (sort-by :name people) if wanted sort name, i'm not sure, syntactically, how example above work.

try:

(sort-by (comp :year :birthday) people)

this sorts on person's year of birth.

comp takes list of functions , composes them single function first takes parameter, runs function on right first, takes result , proceeds leftward.

see comp in clojuredocs details.


Comments

Post a Comment

Popular posts from this blog

javascript - RequestAnimationFrame not working when exiting fullscreen switching space on Safari -

request animation frame stops working when exiting fullscreen clicking on original space's safari window. fine if fullscreen mode canceled escape key or calling cancelfullscreen(). steps reproduce: open https://dl.dropboxusercontent.com/u/769042/prezi/safari-fullscreen.html click "draw raf", kittie appears click "fullscreen", go fullscreen click "draw raf", kittie appears go space original safari was, showing "click exit fullscreen mode", click anywhere, out fullscreen click "draw raf", nothing happens what handling click calling: window.requestanimationframe(draw); which draws on canvas context: function draw() { ctx.drawimage(img, math.random()*500|0, math.random()*400|0, 100, 100); } i checked .hidden , .visibilitystate, updated correctly. tested on osx 10.9.3, safari 7.0.4 (9537.76.4). has workaround/solution other switching old settimeout? this sounds webkit bug 88940 : using reque...
Read more

jsf - How to ajax update an item in the footer of a PrimeFaces dataTable? -

this visual of table have: +---------+------------+-------------------+ | header1 | header2 | header3 | +---------+------------+-------------------+ | row | input | calc'ed output | | row b | input b | calc'ed output b | | etc.. | etc.. | etc.. | +---------+------------+-------------------+ | total: total calc'ed output | +------------------------------------------+ and stripped-down code: <p:datatable id="mytable" value="#{mybean.somelist}" var="currentitem"> <p:column headertext="header1"> <h:outputtext value="#{currentitem.name}" /> </p:column> <p:column headertext="header2"> <pe:inputnumber value="#{currentitem.inputval}"> <p:ajax event="change" listener="#{mybean.changelistener}" update="outputval outputtotal...
Read more

django - CSRF verification failed. Request aborted. CSRF cookie not set -

error: reason given failure: csrf cookie not set. in general, can occur when there genuine cross site request forgery, or when django's csrf mechanism has not been used correctly. post forms, need ensure: browser accepting cookies. view function uses requestcontext template, instead of context. in template, there {% csrf_token %} template tag inside each post form targets internal url. if not using csrfviewmiddleware, must use csrf_protect on views use csrf_token template tag, accept post data. you're seeing section of page because have debug = true in django settings file. change false, , initial error message displayed. can customize page using csrf_failure_view setting. did find, nothing helped, must foolish(( my template <form method="post">{% csrf_token %} {% field in form %} <div class="control-group"> {{ field }} </div> {% endfor %} <input type=...
Read more