Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Unfortunately, the collections hierarchy got itself into a bit of a mess with <code>-</code> on <code>List</code>. For <code>ArrayBuffer</code> it works just like you might hope:</p> <pre><code>scala&gt; collection.mutable.ArrayBuffer(1,2,3,2,4) - 2 res0: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(1, 3, 2, 4) </code></pre> <p>but, sadly, <code>List</code> ended up with a <code>filterNot</code>-style implementation and thus does the "wrong thing" <em>and</em> throws a deprecation warning at you (sensible enough, since it is actually <code>filterNot</code>ing):</p> <pre><code>scala&gt; List(1,2,3,2,4) - 2 warning: there were deprecation warnings; re-run with -deprecation for details res1: List[Int] = List(1, 3, 4) </code></pre> <p>So arguably the easiest thing to do is convert <code>List</code> into a collection that does this right, and then convert back again:</p> <pre><code>import collection.mutable.ArrayBuffer._ scala&gt; ((ArrayBuffer() ++ List(1,2,3,2,4)) - 2).toList res2: List[Int] = List(1, 3, 2, 4) </code></pre> <p>Alternatively, you could keep the logic of the code you've got but make the style more idiomatic:</p> <pre><code>def removeInt(i: Int, li: List[Int]) = { def removeOne(i: Int, left: List[Int], right: List[Int]): List[Int] = right match { case r :: rest =&gt; if (r == i) left.reverse ::: rest else removeOne(i, r :: left, rest) case Nil =&gt; left.reverse } removeOne(i, Nil, li) } scala&gt; removeInt(2, List(1,2,3,2,4)) res3: List[Int] = List(1, 3, 2, 4) </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POWhat is an idiomatic Scala way to "remove" one element from an immutable List?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USRex Kerr
    1. USRex Kerr
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. CO`removeInt(5,List(1,2,6,4,5,3,6,4,6,5,1))` yields `List(4, 6, 2, 1, 3, 6, 4, 6, 5, 1)`. I think this is not what you wanted.
      singulars
      1. PO
      1. USKen Bloom
    2. CO@Ken Bloom - Indeed. It's an error in the original algorithm, which I copied without thinking enough. Fixed now.
      singulars
      1. PO
      1. USRex Kerr
    3. COMore an omission in the question spec, as the order doesn't matter in my specific case. Good to see the order-preserving version though, thanks.
      singulars
      1. PO
      1. USGavilan Comun
 

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