    array.max_by do |element|
      element.field
    end

Or:

    array.max_by(&amp;:field)

Does this help?

    my_array.max {|a,b| a.attr &lt;=&gt; b.attr }

(I assume that your field has name `attr`)

You can also sort the array and then get max, min, second largest value etc.

    array = array.sort_by {|k,v| v}.reverse

    puts hash[0][&quot;key&quot;]

I want know how I can add values to my vector of structs using the `push_back` method

    struct subject
    {
      string name;
      int marks;
      int credits;
    };
    
    
    vector&lt;subject&gt; sub;
    
    
So now how can I add elements to it?
    
I have function that initializes string name(subject name to it)
    
    void setName(string s1, string s2, ...... string s6)
    {
       // how can i set name too sub[0].name= &quot;english&quot;, sub[1].name = &quot;math&quot; etc
      
      sub[0].name = s1 // gives segmentation fault; so how do I use push_back method?
    
      sub.name.push_back(s1);
      sub.name.push_back(s2);
      sub.name.push_back(s3);
      sub.name.push_back(s4);
    
      sub.name.push_back(s6);
    
    }

Function call

    setName(&quot;english&quot;, &quot;math&quot;, &quot;physics&quot; ... &quot;economics&quot;);










Vector of structs initialization

I&#39;m trying to run multiple functions that connect to a remote site (by network) and return a generic list. But I want to run them simultaneously.

For example:

    public static List&lt;SearchResult&gt; Search(string title)
    {
        //Initialize a new temp list to hold all search results
        List&lt;SearchResult&gt; results = new List&lt;SearchResult&gt;();

        //Loop all providers simultaneously
        Parallel.ForEach(Providers, currentProvider =&gt;
        {
            List&lt;SearchResult&gt; tmpResults = currentProvider.SearchTitle((title));

            //Add results from current provider
            results.AddRange(tmpResults);
        });

        //Return all combined results
        return results;
    }

As I see it, multiple insertions to &#39;results&#39; may happend at the same time... Which may crash my application.

How can I avoid this?

Parallel.ForEach with adding to list

There is probably a very simple answer to this question, but I can&#39;t for the life of me figure it out at the moment. If I have a ruby array of a certain type of objects, and they all have a particular field, how do I find the element of the array the has the largest value for that field?

Finding the element of a Ruby array with the maximum value for a particular attribute

<p>There is probably a very simple answer to this question, but I can't for the life of me figure it out at the moment. If I have a ruby array of a certain type of objects, and they all have a particular field, how do I find the element of the array the has the largest value for that field?</p>


I&#39;m working on the file upload portion of a Rails app.  Different types of files are handled differently by the app.

I want to make a whitelist of certain file extensions to check the uploaded files against to see where they should go.  All of the file names are strings.  

I need a way to check only the extension part of the file name string.  The file names are all in the format of &quot;some_file_name.some_extension&quot;.


Find the extension of a filename in Ruby

I just updated to Ruby 1.9.3p0 and Rails 3.1.1. Now when I try to launch the server, it complains that I should install `ruby-debug`, even though it&#39;s already installed.

    % rails server --environment=development --debug
    =&gt; Booting WEBrick
    =&gt; Rails 3.1.0 application starting in development on http://0.0.0.0:3000
    =&gt; Call with -d to detach
    =&gt; Ctrl-C to shutdown server
    You need to install ruby-debug to run the server in debugging mode. With gems, use &#39;gem install ruby-debug&#39;
    Exiting

In my Gemfile I have

    # see: http://stackoverflow.com/questions/1083451/debugging-in-ruby-1-9
    gem &#39;ruby-debug-base19&#39;, &quot;0.11.24&quot;
    gem &#39;ruby-debug19&#39;, &quot;0.11.6&quot;

Is it possible to run debug with the latest version of Ruby?



ruby-debug with Ruby 1.9.3?

There are instances where I would like to revert and uninstall all previous gem installations.

For instance, I needed to assist a friend migrate their rails development machine to use RVM.  As they had been previously using the system-wide `gem`, he was experiencing many headaches when working with multiple projects.  *Essentially, he was the poster-child for an RVM convert.*

How can I elegantly uninstall all of the gems on his OSX system?

Uninstall all installed gems, in OSX?

What is the best way to create an **empty** file in Ruby?

Something similar to the Unix command, [touch][1]:

    touch file.txt

  [1]: https://en.wikipedia.org/wiki/Touch_%28Unix%29


Creating an empty file in Ruby: &quot;touch&quot; equivalent?

I have `ruby 1.9.2p180 (2011-02-18) [i386-mingw32]` installed on my windows 7 machine. Now I tried to install the JSON gem using the command, &quot;gem install json&quot; and got the following error.

    ERROR:  Error installing JSON:
        The &#39;json&#39; native gem requires installed build tools.

    Please update your PATH to include build tools or download the DevKit
    from &#39;[http://rubyinstaller.org/downloads][1]&#39; and follow the instructions
    at &#39;[http://github.com/oneclick/rubyinstaller/wiki/Development-Kit][2]&#39;

Then I went and downloaded DevKit-4.5.0-20100819-1536-sfx.exe. Extracted it to C:\DevKit. And then from the command prompt, I executed the following commands.

    ruby dk.rb init

After the above command is executed, I verified that config.yaml is generated and it has the path for my ruby folder added automatically. This is the line at the bottom of the config.yaml file          &quot;- C:/Ruby192&quot;

    ruby dk.rb review

I got the message that devkit functionality will be injected into the rubies when you run &quot;ruby dk.rb install&quot;

    ruby dk.rb install

I got the following message. 

    [INFO] RubyGems override already in place for C:/Ruby192, skipping.
    [INFO] Installing C:/Ruby192/lib/ruby/site_ruby/devkit.rb


Now I tried executing the JSON gem again using the command `gem install json`. Then got the same error message as before.

    ERROR:  Error installing JSON:
        The &#39;json&#39; native gem requires installed build tools.........

Am I missing something?


  [1]: http://rubyinstaller.org/downloads
  [2]: http://github.com/oneclick/rubyinstaller/wiki/Development-Kit

Content Type	Original Author	Original Content on Stackoverflow
Question	Richard Stokes	View Question on Stackoverflow
Solution 1 - Ruby	David Grayson	View Answer on Stackoverflow
Solution 2 - Ruby	p.matsinopoulos	View Answer on Stackoverflow
Solution 3 - Ruby	Linju	View Answer on Stackoverflow

Finding the element of a Ruby array with the maximum value for a particular attribute

Ruby Problem Overview

Ruby Solutions

Solution 1 - Ruby

Solution 2 - Ruby

Solution 3 - Ruby

Parallel.ForEach with adding to list

Vector of structs initialization

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