enumerable

Equivalent of Ruby Enumerable.collect that returns an Enumerable?

In this code, I create an array of strings "1" to "10000": array_of_strings = (1..10000).collect {|i| String(i)} Does the Ruby Core API provide a way to get an enumerable object that lets me enumerate over the same list, generating the string values on demand, rather than generating an array of the strings? Here's a further example w...

Cast int to Enum in Delphi Prism

Basically the same as this question, but in Delphi Prism: http://stackoverflow.com/questions/29482/cast-int-to-enum-in-c I manage to do it from a string: YourEnum := Enum.Parse(TypeOf(YourEnum), "mystr") as YourEnum But I tried the following, and get a type mismatch error: YourEnum := 3 as YourNum Any ideas what the syntax is for...

Common Ancestor to Java Array and List

In .NET, both array and list have Enumerable as ancestor, so a method that accept Enumerable as an argument can receive both array and list as its argument. I wonder if there is a similar thing in Java? ...

Enumerable giving unexpected output

class Foo { public static IEnumerable<int> Range(int start, int end) { return Enumerable.Range(start, end); } public static void PrintRange(IEnumerable<int> r) { foreach (var item in r) { Console.Write(" {0} ", item); } Console.WriteLine(); } } class Program { ...

NotSupportedException on IQuery's Enumerable when using statelesssession

when trying to use the Enumerable method on a named query, with a Stateless session, as shown in the example at: http://www.nhforge.org/doc/nh/en/#batch-statelesssession i am seeing a NotSupportedException. the stack trace is as below: System.NotSupportedException: Specified method is not supported. at NHibernate.Impl.StatelessSession...

How to create an infinite enumerable of Times?

I want to be able to have an object extend Enumerable in Ruby to be an infinite list of Mondays (for example). So it would yield: March 29, April 5, April 12...... etc How can I implement this in Ruby? ...

How to iterate multiple enumerables in ruby?

I know two arrays can be zipped and the result can be iterated with #each. But how do you do it with an unknown number of enumerables? Let's say anand = %w(1-0 0.5-0.5 0.5-0.5 1.0) carlsen = %w(0-1 0.5-0.5 0.5-0.5 1.0) kramnik = %w(0.5-0.5 0.5-0.5 0.5-0.5 1.0) players= [anand, carlsen, kramnik] #something smart players.each{|round|puts...

Calculate sum of objects for each unique object property in Ruby

I was helping with an answer in this question and it sparked a question of my own. Pie is an object that has a pieces array made of of PiePiece objects. Each PiePiece has a flavor attribute How do I create a hash that looks like this: # flavor => number of pieces { :cherry => 3 :apple => 1 :strawberry => 2 } This works, but ...

how does Enumerable#cycle work? (ruby)

looper = (0..3).cycle 20.times { puts looper.next } can I somehow find the next of 3? I mean if I can get .next of any particular element at any given time. Not just display loop that starts with the first element. UPDATE Of course I went though ruby doc before posting my question. But I did not find answer there ... UPDATE2 input ...

IEnumerable doesn't have Count

I have the following method: public bool IsValid { get { return (GetRuleViolations().Count() == 0); } } public IEnumerable<RuleViolation> GetRuleViolations(){ //code here } Why is it that when I do .Count above it is underlined in red? I got the following error: Error 1 'System.Collections.Generic.IEnumerable' does not c...

Problem in populating a dictionary using Enumerable.Range()

If I do for (int i = 0; i < appSettings.Count; i++) { string key = appSettings.Keys[i]; euFileDictionary.Add(key, appSettings[i]); } It is working fine. When I am trying the same thing using Enumerable.Range(0, appSettings.Count).Select(i => { string Key = appSettings.Keys[i]; string Value = appSettings[i]; euFileDic...

Is there anything like Enumerable.Range(x,y) in Java?

Hello there. Is there something like C#/.NET's IEnumerable<int> range = Enumerable.Range(0, 100); //.NET in Java? ...

Clean solution to this ruby iterator trickiness?

k = [1,2,3,4,5] for n in k puts n if n == 2 k.delete(n) end end puts k.join(",") # Result: # 1 # 2 # 4 # 5 # [1,3,4,5] # Desired: # 1 # 2 # 3 # 4 # 5 # [1,3,4,5] This same effect happens with the other array iterator, k.each: k = [1,2,3,4,5] k.each do |n| puts n if n == 2 k.delete(n) end end puts k.join(",") ha...

Understanding Ruby Enumerable#map (with more complex blocks)

Let's say I have a function def odd_or_even n if n%2 == 0 return :even else return :odd end end And I had a simple enumerable array simple = [1,2,3,4,5] And I ran it through map, with my function, using a do-end block: simple.map do |n| odd_or_even(n) end # => [:odd,:even,:odd,:even,:odd] How could I do this with...

Please explain System.Linq.Enumerable.Where(Func<T, int, bool> predicate)

I can't make any sense of the MSDN documentation for this overload of the Where method that accepts a predicate that has two arguments where the int, supposedly, represents the index of the source element, whatever that means (I thought an enumerable was a sequence and you couldn't see further than the next item, much less do any indexin...

Is there a way to specify an anonymous empty enumerable type?

I'm returning a Json'ed annonymous type: IList<MyClass> listOfStuff = GetListOfStuff(); return Json( new { stuff = listOfStuff } ); In certain cases, I know that listOfStuff will be empty. So I don't want the overhead of calling GetListOfStuff() (which makes a database call). So in this case I'm writing: return Json( ...

Prototype cannot read its own Objects?

I need to parse a URL and be sure there are no duplicate keys in the query string. I've converted the query string to an object using String#toQueryParams() var queryString = this.parseUri(uri).query.toQueryParams(); On an alert, this comes up as [Object object], but... queryString.each(function(e) {... }); I get the error that que...

Why Ruby on Rails' Enumerable shows count of 3 but ".each" prints out item 1 time only

I have a Enumerable object returned from Mongoid (MongoDB object mapper) using HAML: = @employees.count = @employees.class - @employees.each do |e| =h e.inspect the count shows 3 the class shows Enumerable::Enumerator But only 1 item is printed out the object is returned in the controller using @employees = Employee.limit...

Why does Enumerable.ToLookup<>() return an ILookup<,> and not a Lookup<,>?

There is one method in Lookup<,> that is not in ILookup<,>: public IEnumerable<TResult> ApplyResultSelector<TResult>( Func<TKey, IEnumerable<TElement>, TResult> resultSelector); Why is the return type of Enumerable.ToLookup<>() declared to be ILookup<,> despite the fact that it always seems to return an instance of Lookup<,>? If t...

rails toggle problem - ActionView::TemplateError (undefined method `[]' for #<Enumerable::Enumerator

After this rails app has been running fine for over two years... just started getting this one error on only one page. ActionView::TemplateError (undefined method `[]' for #<Enumerable::Enumerator:0xb25fbc4>) on line #10 of app/views/notes/_form.rhtml: 7: <%= @n.text_field 'note', :size => 55 %> 8: </label> 9: <%= link_to_function('Cu...