Databases
StackOverflow2013
Postsdbo
POEric Lippert's challenge "comma-quibbling", best answer?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POEric Lippert's challenge "comma-quibbling", best answer?
    primarykey
    data
    text
    <p>I wanted to bring this challenge to the attention of the stackoverflow community. The original problem and answers are <a href="http://blogs.msdn.com/ericlippert/archive/2009/04/15/comma-quibbling.aspx" rel="nofollow noreferrer">here</a>. BTW, if you did not follow it before, you should try to read Eric's blog, it is pure wisdom.</p> <p><strong>Summary:</strong></p> <p>Write a function that takes a non-null IEnumerable and returns a string with the following characteristics:</p> <ol> <li>If the sequence is empty the resulting string is "{}".</li> <li>If the sequence is a single item "ABC" then the resulting string is "{ABC}".</li> <li>If the sequence is the two item sequence "ABC", "DEF" then the resulting string is "{ABC and DEF}".</li> <li>If the sequence has more than two items, say, "ABC", "DEF", "G", "H" then the resulting string is "{ABC, DEF, G and H}". (Note: no Oxford comma!)</li> </ol> <p>As you can see even our very own Jon Skeet (yes, it is well known that <a href="https://stackoverflow.com/questions/305223/jon-skeet-facts">he can be in two places at the same time</a>) has posted a solution but his (IMHO) is not the most elegant although probably you can not beat its performance.</p> <p>What do you think? There are pretty good options there. I really like one of the solutions that involves the select and aggregate methods (from Fernando Nicolet). Linq is very powerful and dedicating some time to challenges like this make you learn a lot. I twisted it a bit so it is a bit more performant and clear (by using Count and avoiding Reverse):</p> <pre><code>public static string CommaQuibbling(IEnumerable&lt;string&gt; items) { int last = items.Count() - 1; Func&lt;int, string&gt; getSeparator = (i) =&gt; i == 0 ? string.Empty : (i == last ? " and " : ", "); string answer = string.Empty; return "{" + items.Select((s, i) =&gt; new { Index = i, Value = s }) .Aggregate(answer, (s, a) =&gt; s + getSeparator(a.Index) + a.Value) + "}"; } </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCommunity
    1. USMMind
    plurals
    1. PL
      singulars
      1. LTLinked
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POEric Lippert's challenge "comma-quibbling", best answer?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POEric Lippert's challenge "comma-quibbling", best answer?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POEric Lippert's challenge "comma-quibbling", best answer?
      1. This table or related slice is empty.
      1. VTUpMod
    1. CONote that using Count instead of Reverse won't necessarily improve performance: If the string collection doesn't implement ICollection then Count will need to iterate through it entirely.
      singulars
      1. POEric Lippert's challenge "comma-quibbling", best answer?
      1. USLukeH
    2. COLet me get it correctly wasn't this question supposed to identify best "LINQ" way of solving problem rather then trivial procedural way of using an enumerator ??
      singulars
      1. POEric Lippert's challenge "comma-quibbling", best answer?
      1. USAkash Kava
    3. COThe author of the original challenge said: "I am particularly interested in solutions which make the semantics of the code very clear to the code maintainer". In my opinion, some of the higher votes violates that. Yes they are clever and perform well, but I find them hard to read.
      singulars
      1. POEric Lippert's challenge "comma-quibbling", best answer?
      1. USThomas Eyde
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload