A lot of people using `sprintf` (which is the right thing to do), and I think if you want to do this **for a string** it&#39;s best to keep in mind the `rjust` and `ljust` methods:

    &quot;4&quot;.rjust(2, &#39;0&#39;)

This will make the `&quot;4&quot;` right justified by ensuring it&#39;s at least `2` characters long and pad it with `&#39;0&#39;`. `ljust` does the opposite.

Did you mean `sprintf &#39;%02d&#39;, n`?

    irb(main):003:0&gt; sprintf &#39;%02d&#39;, 1
    =&gt; &quot;01&quot;
    irb(main):004:0&gt; sprintf &#39;%02d&#39;, 10
    =&gt; &quot;10&quot;

You might want to reference the [format table for `sprintf`][1] in the future, but for this particular example `&#39;%02d&#39;` means to print an integer (`d`) taking up at least 2 characters (`2`) and left-padding with zeros instead of spaces (`0`).


  [1]: http://ruby-doc.org/core/classes/Kernel.html#M005962

how about `&quot;%02d&quot; % 9`? see http://www.ruby-doc.org/core-2.0/String.html#method-i-25 and http://www.ruby-doc.org/core-2.0/Kernel.html#method-i-sprintf .

Try this, it should work:

```ruby
abc = 5
puts &quot;%.2i&quot; % abc # =&gt; 05

abc = 5.0
puts &quot;%.2f&quot; % abc # =&gt; 5.00
```

[Rubocop][1] recommends `format` over `sprintf` and `%`. I think it&#39;s more intuitive:

```
format(&#39;%02d&#39;, 7) # =&gt; &quot;07&quot;
format(&#39;%02d&#39;, 12) # =&gt; &quot;12&quot;
```


  [1]: https://www.rubydoc.info/gems/rubocop/RuboCop/Cop/Style/FormatString

There is another similar question to mine on StackOverflow ([How to get creation date of a file in Java][1]), but the answer isn&#39;t really there as the OP had a different need that could be solved via other mechanisms.  I am trying to create a list of the files in a directory that can be sorted by age, hence the need for the file creation date.

I haven&#39;t located any good way to do this after much trawling of the web.  Is there a mechanism for getting file creation dates?

BTW, currently on a Windows system, may need this to work on a Linux system as well.  Also, I can&#39;t guarantee that a file naming convention would be followed where the creation date/time is embedded in the name.


  [1]: https://stackoverflow.com/questions/741466/how-to-get-creation-date-of-a-file-in-java

Determine file creation date in Java

I am playing around with the Oauth 2.0 authorization in Facebook and was wondering if the access tokens Facebook passes out ever expire. If so, is there a way to request a long-life access token?

Do Facebook Oauth 2.0 Access Tokens Expire?

I&#39;m looking to convert single digit numbers to two-digit numbers like so:

    9 ==&gt; 09
    5 ==&gt; 05
    12 == 12
    4 ==&gt; 04

I figure I could put a bunch of if-else statements (if number is under 10, then do a gsub) but figure that&#39;s horrible coding. I know Rails has number_with_precision but I see that it only applies to decimal numbers. Any ideas on how to convert single-digits to two-digits?

Ruby on Rails: How do you add add zeros in front of a number if it&#39;s under 10?

I'm looking to convert single digit numbers to two-digit numbers like so:
<pre><code class="hljs language-ini">9 ==> 09
5 ==> 05
12 == 12
4 ==> 04
</code></pre>
I figure I could put a bunch of if-else statements (if number is under 10, then do a gsub) but figure that's horrible coding. I know Rails has number_with_precision but I see that it only applies to decimal numbers. Any ideas on how to convert single-digits to two-digits?

I&#39;m having difficultly adding querystring parameters to link_to UrlHelper.  I have an Index view, for example, that has UI elements for sorting, filtering, and pagination (via will_paginate).  The will_paginate plugin manages the intra-page persistence of querystring parameters correctly.

Is there an automatic mechanism to add the querystring parameters to a give named route, or do I need to do so manually?  A great deal of research on this seemingly simple construct has left me clueless.

**Edit**

Some of the challenges:

 1. If I have two querystring parameters, bucket &amp; sorting, how do set a specific value to one of these in a link_to, while preserving the current value of the other?  For example:

        &lt;%= link_to &quot;0&quot;, profiles_path(:bucket =&gt; &#39;0&#39;, :sorting=&gt;?? ) %&gt;

 2. If I have multiple querystring parameters, bucket &amp; sorting &amp; page_size, and I want to set the value to one of these, is there a way to &#39;automatically&#39; include the names and values of the remaining parameters?  For example:

        &lt;%= link_to &quot;0&quot;, profiles_path(:bucket =&gt; &#39;0&#39;, [include sorting and page_size name/values here] ) %&gt;

 3. The will_paginate plugin manages its page variable and other querystring variables automatically.  There doesn&#39;t seem to be an automatic UI element for managing page size.  While I&#39;ve seen code to create a select list of page sizes, I would rather have A elements for this (like SO).  Part of this challenge is related to #2, part is related to hiding/showing this UI element based on the existence/non-existence of records.  Said another way, I only want to include page-size links if there are records to page.  Moreover, I prefer to automatically include the other QS variables (i.e. page, bucket, sorting), rather than having to include them by name in the link_to.

Add querystring parameters to link_to

In Ruby/Rails, how do I convert a UTC DateTime to another time zone?

Rails: convert UTC DateTime to another time zone

So, we have an existing Rails 2.3.5 app that does not support Internationalization at all. Now, I&#39;m well familiar with Rails I18n stuff, but we have a LOT of output strings inside `/javascripts/`. I&#39;m not a huge fan of this approach, but unfortunately it is too late to fix it now.

How might we internationalize strings stored in JS files in a Rails app? Rails doesn&#39;t even serve the JS files...

I&#39;m thinking I could always have the Rails app serve up the JS files, but that seems pretty gross. Are there plugins to do this?

Rails: Internationalization of Javascript Strings?

I see both in examples when checking what env one is running in.  What&#39;s preferred?  Are they, for all intents and purposes equal?

Rails.env vs RAILS_ENV

I&#39;m in need of getting a random record from a table via ActiveRecord. I&#39;ve followed the example from [Jamis Buck from 2006][1].

However, I&#39;ve also come across another way via a Google search (can&#39;t attribute with a link due to new user restrictions):

     rand_id = rand(Model.count)
     rand_record = Model.first(:conditions =&gt; [&quot;id &gt;= ?&quot;, rand_id])

I&#39;m curious how others on here have done it or if anyone knows what way would be more efficient.

[1]: http://weblog.jamisbuck.org/2006/10/7/helping-activerecord-finders-help-you


Random record in ActiveRecord

Specifically, the ruby-oci8 gem.  I have both 1.0.7 and 2.0.4 installed.  I want 1.0.7.

I can just require oci8, but I don&#39;t get the version I want.

    irb(main):001:0&gt; require &#39;oci8&#39;
    =&gt; true
    irb(main):002:0&gt; OCI8::VERSION
    =&gt; &quot;2.0.4&quot;

I can require using the full path to the file, which works, but is not going to be portable:

    irb(main):001:0&gt; require &#39;C:\Ruby\lib\ruby\gems\1.8\gems\ruby-oci8-1.0.7-x86-mswin32-60\lib\oci8&#39;
    =&gt; true
    irb(main):002:0&gt; OCI8::VERSION
    =&gt; &quot;1.0.7&quot;

I can use the gem command to ask for the version I want, but it doesn&#39;t appear to actually load the library:

    irb(main):001:0&gt; gem &#39;ruby-oci8&#39;, :lib=&gt;&#39;oci8&#39;, :version=&gt;&#39;=1.0.7&#39;
    =&gt; true
    irb(main):002:0&gt; OCI8::VERSION
    NameError: uninitialized constant OCI8
        from (irb):2

I would definitely favor this last approach if would load the library, rather than just confirming that it&#39;s present on my system.  What am I missing?

How do I require a specific version of a ruby gem?

Consider this code:

    h = Hash.new(0)  # New hash pairs will by default have 0 as values
    h[1] += 1  #=&gt; {1=&gt;1}
    h[2] += 2  #=&gt; {2=&gt;2}

That’s all fine, but:

    h = Hash.new([])  # Empty array as default value
    h[1] &lt;&lt;= 1  #=&gt; {1=&gt;[1]}                  ← Ok
    h[2] &lt;&lt;= 2  #=&gt; {1=&gt;[1,2], 2=&gt;[1,2]}      ← Why did `1` change?
    h[3] &lt;&lt; 3   #=&gt; {1=&gt;[1,2,3], 2=&gt;[1,2,3]}  ← Where is `3`?

At this point I expect the hash to be:

    {1=&gt;[1], 2=&gt;[2], 3=&gt;[3]}

but it’s far from that. What is happening and how can I get the behavior I expect?

Strange, unexpected behavior (disappearing/changing values) when using Hash default value, e.g. Hash.new([])

I have an array

    foo = %w(1 2 3 4 5 6 7 8 9 10)

How can I split or &quot;chunk&quot; this into smaller arrays?

    class Array
      def chunk(size)
        # return array of arrays
      end
    end
    
    foo.chunk(3)
    # =&gt; [[1,2,3],[4,5,6],[7,8,9],[10]]

How to split (chunk) a Ruby array into parts of X elements?

In Ruby, what&#39;s the best way to convert a string of the format: `&quot;{ 2009, 4, 15 }&quot;` to a Date?

Content Type	Original Author	Original Content on Stackoverflow
Question	sjsc	View Question on Stackoverflow
Solution 1 - Ruby on-Rails	Ryan Bigg	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails	Mark Rushakoff	View Answer on Stackoverflow
Solution 3 - Ruby on-Rails	ax.	View Answer on Stackoverflow
Solution 4 - Ruby on-Rails	Salil	View Answer on Stackoverflow
Solution 5 - Ruby on-Rails	Washington Botelho	View Answer on Stackoverflow

Ruby on Rails: How do you add add zeros in front of a number if it's under 10?

Ruby on-Rails Problem Overview

Ruby on-Rails Solutions

Solution 1 - Ruby on-Rails

Solution 2 - Ruby on-Rails

Solution 3 - Ruby on-Rails

Solution 4 - Ruby on-Rails

Solution 5 - Ruby on-Rails

Do Facebook Oauth 2.0 Access Tokens Expire?

Determine file creation date in Java

Attributions