Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>No, you don't need to search through all possible alternatives. A simple recursive algorithm (like the one given by @recursive) will give you the answer. If you are looking for a function that actually outputs all of the combinations, rather than just how many, here is a version written in R. I don't know what language you are working in, but it should be pretty straightforward to translate this into anything, although the code might be longer, since R is good at this kind of thing.</p> <pre><code>allCombos&lt;-function(len, ## number of items to sample x, ## array of quantities of balls, by color names=1:length(x) ## names of the colors (defaults to "1","2",...) ){ if(length(x)==0) return(c()) r&lt;-c() for(i in max(0,len-sum(x[-1])):min(x[1],len)) r&lt;-rbind(r,cbind(i,allCombos(len-i,x[-1]))) colnames(r)&lt;-names r } </code></pre> <p>Here's the output:</p> <pre><code>&gt; allCombos(3,c(3,3),c("white","black")) white black [1,] 0 3 [2,] 1 2 [3,] 2 1 [4,] 3 0 &gt; allCombos(10,c(15,1,1,1,1,1),c("white","black","blue","red","yellow","green")) white black blue red yellow green [1,] 5 1 1 1 1 1 [2,] 6 0 1 1 1 1 [3,] 6 1 0 1 1 1 [4,] 6 1 1 0 1 1 [5,] 6 1 1 1 0 1 [6,] 6 1 1 1 1 0 [7,] 7 0 0 1 1 1 [8,] 7 0 1 0 1 1 [9,] 7 0 1 1 0 1 [10,] 7 0 1 1 1 0 [11,] 7 1 0 0 1 1 [12,] 7 1 0 1 0 1 [13,] 7 1 0 1 1 0 [14,] 7 1 1 0 0 1 [15,] 7 1 1 0 1 0 [16,] 7 1 1 1 0 0 [17,] 8 0 0 0 1 1 [18,] 8 0 0 1 0 1 [19,] 8 0 0 1 1 0 [20,] 8 0 1 0 0 1 [21,] 8 0 1 0 1 0 [22,] 8 0 1 1 0 0 [23,] 8 1 0 0 0 1 [24,] 8 1 0 0 1 0 [25,] 8 1 0 1 0 0 [26,] 8 1 1 0 0 0 [27,] 9 0 0 0 0 1 [28,] 9 0 0 0 1 0 [29,] 9 0 0 1 0 0 [30,] 9 0 1 0 0 0 [31,] 9 1 0 0 0 0 [32,] 10 0 0 0 0 0 &gt; </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POFinding all subsets of a multiset
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USmrip
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POFinding all subsets of a multiset
      singulars
      1. PTQuestion
    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. VTAcceptedByOriginator
    1. COThanks a lot, it's exactly what I was looking for. It was a pain to convert it into Perl, though...
      singulars
      1. PO
      1. USStamm
 

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