The [`chars` method][1] returns an enumeration of the string&#39;s characters.

    str.chars.sort.join
    #=&gt; &quot;Sginrt&quot;

To sort case insensitively:

    str.chars.sort(&amp;:casecmp).join
    #=&gt; &quot;ginrSt&quot;

[1]:http://ruby-doc.org/core-1.9.3/String.html#method-i-chars

Also (just for fun)

    str = &quot;String&quot;
    str.chars.sort_by(&amp;:downcase).join
    #=&gt; &quot;ginrSt&quot;

You can transform the string into an array to sort:

    &#39;string&#39;.split(&#39;&#39;).sort.join

    str.unpack(&quot;c*&quot;).sort.pack(&quot;c*&quot;)

If you deal with Unicode text, you might prefer to use [`String#grapheme_clusters`](https://ruby-doc.org/core-3.1.2/String.html#method-i-grapheme_clusters):

```ruby
&quot;a\u0300e&quot;.chars.sort.join
=&gt; &quot;aè&quot; # diacritic moved!
&quot;a\u0300e&quot;.grapheme_clusters.sort.join
=&gt; &quot;àe&quot; # expected result
```

I find myself wanting to delete rows older than (x)-days on a rolling basis in a lot of applications. What is the best way to do this most efficiently on a high-traffic table?

For instance, if I have a table that stores notifications and I only want to keep these for 7 days. Or high scores that I only want to keep for 31 days.

Right now I keep a row storing the epoch time posted and run a cron job that runs once per hour and deletes them in increments like this:

    DELETE FROM my_table WHERE time_stored &lt; 1234567890 LIMIT 100

I do that until mysql_affected_rows returns 0.

I used to do it all at once but that caused everything in the application to hang for 30 seconds or so while INSERTS piled up. Adding the LIMIT worked to alleviate this but I&#39;m wondering if there is a better way to do this.

What is the best way to delete old rows from MySQL on a rolling basis?

Hi can somebody tell me what is the wrong in the below code?

Selected=&quot;selected&quot; not working for me.

    &lt;!DOCTYPE HTML PUBLIC &quot;-//W3C//DTD HTML 4.0 Transitional//EN&quot;&gt;
        &lt;select id=&quot;tstselect&quot; name=&quot;tstselect&quot; onchange=&quot;showselected(this.value);&quot;&gt;
        &lt;option value=&quot;0&quot; &gt;0&lt;/option&gt;
        &lt;option value=&quot;1&quot; &gt;1&lt;/option&gt;
        &lt;option value=&quot;2&quot; &gt;2&lt;/option&gt;
        &lt;option value=&quot;3&quot; selected=&quot;selected&quot;&gt;3&lt;/option&gt;
        &lt;/select&gt;

Thanks in advance


HTML selected=&quot;selected&quot; not working

For Array, there is a pretty `sort` method to rearrange the sequence of elements. I want to achieve the same results for a String.

For example, I have a string `str = &quot;String&quot;`, I want to sort it alphabetically with one simple method to `&quot;ginrSt&quot;`.
      
Is there a native way to enable this or should I include mixins from `Enumerable`?

How to sort a string&#39;s characters alphabetically?

For Array, there is a pretty <code>sort</code> method to rearrange the sequence of elements. I want to achieve the same results for a String.
For example, I have a string <code>str = "String"</code>, I want to sort it alphabetically with one simple method to <code>"ginrSt"</code>.
Is there a native way to enable this or should I include mixins from <code>Enumerable</code>?

What&#39;s the difference between `to_a` and `to_ary`?


What&#39;s the difference between to_a and to_ary?

In Ruby, I have been told that when doing

    require &quot;some_file&quot;

Ruby will look for the file in certain places.

I know that it looks for `some_file.rb`, but where does it look for it by default?
    

What are the paths that &quot;require&quot; looks up by default?

I have installed gem on Ubuntu 10.10 32 bit with 

    apt-get install gem -y

But when I try to run

    gem install something.gem

I get the error of the command not being found.

    bash: gem: command not found

I installed gem, is there any reason it is saying it can&#39;t find the command?


These files were install by gem package

http://pastie.org/3483416

Gem Command not found

I&#39;m putting in a reaper line into a rake task to kill some additionally spawned ruby tasks as they somehow creep up on occasion.


    system &quot;ps aux | grep &#39;namespace:taskname&#39; | grep ruby | grep -v grep | awk &#39;{print $2}&#39; | xargs kill -9; echo &#39;Reaped old namespace:taskname processes.&#39;&quot;

I&#39;d like to add `grep -v $PID_OF_CURRENT_TASK` in that just to be sure I don&#39;t kill the current task that&#39;s running as well.

How do I get that PID?

How to get PID of current rake task?

I am trying to convert a name from snake case to camel case. Are there any built-in methods?

Eg: `&quot;app_user&quot;` to `&quot;AppUser&quot;`

(I have a string `&quot;app_user&quot;` I want to convert that to model `AppUser`).

Converting string from snake_case to CamelCase in Ruby

Is it possible to split a string every nth character?

For example, suppose I have a string containing the following:

    &#39;1234567890&#39;

How can I get it to look like this:

    [&#39;12&#39;,&#39;34&#39;,&#39;56&#39;,&#39;78&#39;,&#39;90&#39;]



Split string every nth character?

Why doesn&#39;t `&#39;example&#39;[999:9999]` result in error? Since `&#39;example&#39;[9]` does, what is the motivation behind it?

From this behavior I can assume that `&#39;example&#39;[3]` is, essentially/internally, not the same as `&#39;example&#39;[3:4]`, even though both result in the same `&#39;m&#39;` string.

Why does substring slicing with index out of range work?

I&#39;m looking for a way to securely store an API key in a WP7 application. The key is a string and is currently hard coded into the code (see below). I know that someone with a reflector program could easily view this. Is there a better way to package this key as part of my app? Would a resource be more secure?

    string key = &quot;DSVvjankjnersnkaecjnDFSD44VDS23423423rcsedzcadERVSDRFWESDVTsdt&quot;;
(This isn&#39;t actually the key ;) )

Thank you in advance.

How can I securely embed a static string (key) in C#?

&gt; **Possible Duplicate:**  
&gt; [Why can&amp;#39;t strings be mutable in Java and .NET?](https://stackoverflow.com/questions/93091/why-cant-strings-be-mutable-in-java-and-net)  
&gt; [Why .NET String is immutable?](https://stackoverflow.com/questions/2365272/why-net-string-is-immutable)

Several languages have chosen for this, such as C#, Java, and Python.  If it is intended to save memory or gain efficiency for operations like *compare*, what effect does it have on concatenation and other modifying operations?

Why are strings immutable in many programming languages?

I have a CSV-like file, and I would like to sort it by column priority, like [&quot;ORDER BY&quot; in SQL](https://dev.mysql.com/doc/refman/8.0/en/sorting-rows.html). For example, given the following rows,

    3;1;2
    1;3;2
    1;2;3
    2;3;1
    2;1;3
    3;2;1

If &quot;ORDER BY&quot; were `column2, column1, column3`, the result would be:

    2;1;3
    3;1;2
    1;2;3
    3;2;1
    1;3;2
    2;3;1

I&#39;d like to know how to get this same result using the `sort` command on Unix.

Sort CSV file by multiple columns using the &quot;sort&quot; command

I have an array populated by dictionaries, and I need to sort the array alphabetically by the values of one of the keys of the dictionaries.

This is my array:

    tu dictus: (
        {
        brand = Ryul;
        productTitle = Any;
        quantity = 1;
        subBrand = &quot;Ryul INJ&quot;;
        type = Product;
    },
        {
        brand = Trol;
        productTitle = Different;
        quantity = 2;
        subBrand = &quot;&quot;;
        type = Brand;
    },
        {
        brand = Dtor;
        productTitle = Any;
        quantity = 1;
        subBrand = &quot;&quot;;
        type = Product;
    },
        {
        brand = Ryul;
        productTitle = Different;
        quantity = 2;
        subBrand = &quot;Ryul CHES&quot;;
        type = SubBrand;
    },
        {
        brand = Anan;
        productTitle = Any;
        quantity = 1;
        subBrand = &quot;&quot;;
        type = Product;
    }
    )


Normally for sorting an array I will use 

    myArray = [uniqueProdsArray sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];

But how do sort using the `brand` key of the dictionary?

Sorting NSArray of dictionaries by value of a key in the dictionaries

Let&#39;s suppose I wanted a sort function that returns a sorted copy of the inputted array. I naively tried this

    function sort(arr) {
      return arr.sort();
    }

and I tested it with this, which shows that my `sort` method is mutating the array.

    var a = [2,3,7,5,3,7,1,3,4];
    sort(a);
    alert(a);  //alerts &quot;1,2,3,3,3,4,5,7,7&quot;

I also tried this approach

    function sort(arr) {
      return Array.prototype.sort(arr);
    }

but it doesn&#39;t work at all.

Is there a straightforward way around this, preferably a way that doesn&#39;t require hand-rolling my own sorting algorithm or copying every element of the array into a new one?

How can you sort an array without mutating the original array?

I have created a sqlite database which has a table which stores temperature values. The temperature values are written to the database in ascending order for the first time. Then I read the temperature values from the database into a list and then add that list to a combo box to select temperatures - works fine. 

The resulting list is, say:

    templist = [&#39;25&#39;, &#39;50&#39;, &#39;100&#39;, &#39;150&#39;, &#39;200&#39;, &#39;250&#39;, &#39;300&#39;].

Then I add a new temperature value, say, &#39;33&#39; to the database. 

It gets appended to the end of the table. If I read the temperatures now, the list will become: 

    [&#39;25&#39;, &#39;50&#39;, &#39;100&#39;, &#39;150&#39;, &#39;200&#39;, &#39;250&#39;, &#39;300&#39;, &#39;33&#39;]. 

If I do `templist.sort()` or `sorted(templist)`, the end result is 

    [&#39;150&#39;, &#39;200&#39;, &#39;25&#39;, &#39;250&#39;, &#39;300&#39;, &#39;33&#39;, &#39;50&#39;]

Is there any simple way to sort the list in ascending order so that I get:

    [&#39;25&#39;, &#39;33&#39;, &#39;50&#39;, &#39;100&#39;, &#39;150&#39;, &#39;200&#39;, &#39;250&#39;, &#39;300&#39;]

Sort a list of numerical strings in ascending order

Say I have two lists:

    list1 = [3, 2, 4, 1, 1]
    list2 = [&#39;three&#39;, &#39;two&#39;, &#39;four&#39;, &#39;one&#39;, &#39;one2&#39;]

If I run `list1.sort()`, it&#39;ll sort it to `[1,1,2,3,4]` but is there a way to get `list2` in sync as well (so I can say item `4` belongs to `&#39;three&#39;`)?  So, the expected output would be:
```
list1 = [1, 1, 2, 3, 4]
list2 = [&#39;one&#39;, &#39;one2&#39;, &#39;two&#39;, &#39;three&#39;, &#39;four&#39;]
```
My problem is I have a pretty complex program that is working fine with lists but I sort of need to start referencing some data. I know this is a perfect situation for dictionaries but I&#39;m trying to avoid dictionaries in my processing because I do need to sort the key values (if I must use dictionaries I know how to use them).

Basically the nature of this program is, the data comes in a random order (like above), I need to sort it, process it and then send out the results (order doesn&#39;t matter but users need to know which result belongs to which key). I thought about putting it in a dictionary first, then sorting list one but I would have no way of differentiating of items in the with the same value if order is not maintained (it may have an impact when communicating the results to users).  So ideally, once I get the lists I would rather figure out a way to sort both lists together.  Is this possible?

Content Type	Original Author	Original Content on Stackoverflow
Question	steveyang	View Question on Stackoverflow
Solution 1 - Ruby	molf	View Answer on Stackoverflow
Solution 2 - Ruby	fl00r	View Answer on Stackoverflow
Solution 3 - Ruby	imtk	View Answer on Stackoverflow
Solution 4 - Ruby	user2386335	View Answer on Stackoverflow
Solution 5 - Ruby	psychoslave	View Answer on Stackoverflow

How to sort a string's characters alphabetically?

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HTML selected="selected" not working

What is the best way to delete old rows from MySQL on a rolling basis?

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