What does this code in ruby do? -


i new here please gentle me , i'm still newbie in programming , in ruby language.

this combo box , want know goes after change or function calls. can please tell me goes or does? thanks

<p><%= f.select :done_ratio, ((0..100).step(1).to_a.collect {|r| ["#{r} %", r] }), :required => @issue.required_attribute?('done_ratio') %></p>

it creating html select (dropdown) box, values: 0 %, 1 %, 2 %, ..., 100 %.

the field submitted part of form. may or may not required field, depending on value of @issue.required_attribute?('done_ratio'). (this presumably method in issue model, can found in ./app/models/issue.rb.)

breaking down:

  • (0..100) -- creating range object, 0 100 (inclusive).
  • .step(1) -- not needed; delete it. it's saying "step through range 1 @ time" (which default anyway). converts range enumerator.
  • .to_a -- not needed; delete it. converting enumerator array.
  • .collect {|r| ["#{r} %", r] } -- mapping array new list of arrays, like: [["0 %", 0], ["1 %", 1], ..., ["100 %", 100]]. (this method work fine on range or enumerator object, since both classes include this method enumerable module. hence why above 2 steps can both removed!)
  • f.select :done_ratio, (...) -- creating html select element called done_ratio, above names/values.

Comments

Post a Comment

Popular posts from this blog

Is there a better way to structure post methods in Class Based Views -

i'm using class based views in django , never specify url in ajax calls , omit action parameter in form because know these requests go through post method of class based view. notice view - profile page make many requests depending on user updating on page - post method become convoluted , if/else mess example: def post(self, request, *args, **kwargs): # handle user changing available date if request.post.get('availabledate') != none: self.updateavailabledate(request) return jsonresponse({'result':'success'}) if request.post.get('newprojectname') != none: creative_user = creativeuserprofile.objects.get(id = request.user.id) project = project.create_project(creative_user, request.post['newprojectname']) project.save() return jsonresponse({'projectid': project.id }) if request.post.get('projectimage') != none , request.files['file']: proj
Read more

performance - Why is XCHG reg, reg a 3 micro-op instruction on modern Intel architectures? -

i'm doing micro-optimization on performance critical part of code , came across sequence of instructions (in at&t syntax): add %rax, %rbx mov %rdx, %rax mov %rbx, %rdx i thought had use case xchg allow me shave instruction , write: add %rbx, %rax xchg %rax, %rdx however, dimay found agner fog's instruction tables , xchg 3 micro-op instruction 2 cycle latency on sandy bridge, ivy bridge, broadwell, haswell , skylake. 3 whole micro-ops , 2 cycles of latency! 3 micro-ops throws off 4-1-1-1 cadence , 2 cycle latency makes worse original in best case since last 2 instructions in original might execute in parallel. now... cpu might breaking instruction micro-ops equivalent to: mov %rax, %tmp mov %rdx, %rax mov %tmp, %rdx where tmp anonymous internal register , suppose last 2 micro-ops run in parallel latency 2 cycles. given register renaming occurs on these micro-architectures, though, doesn't make sense me done way. why wouldn't register renamer
Read more

jquery - Responsive Navbar with Sub Navbar -

good day, forgive me nav vocabulary not best. if question confusing apologize. i'm working on navigation bar needs centered on page @ 768px , above. items in nav open (or perhaps toggle) subnav lives directly below. these nav should appear centered on page. i have been able work through responsive portion of nav bar, having main items align vertically , sub nav menu of each item roll out below, , gave them indent separation. working well. however, issue not responsive side, behavior @ width greater 768px. happens toggling menu's sub navigation pushes other main items down page below sub nav. here's code: $(document).ready(function () { //stick in fixed 100% height behind navbar don't wrap $('#slide-nav.navbar-inverse').after($('<div class="inverse" id="navbar-height-col"></div>')); $('#slide-nav.navbar-default').after($('<div id="navbar-height-col"></d
Read more