picking 6 unique #s from 1-14 2

[DaveC426913]

Rusty on JavaScript.

I have a list of 14 text strings of which I want to randomly pick 6 unique ones.

for (i=1;i<=6;i++){
tmp = Math.round(Math.random()*14)+1;
for (j=1;j<i;j++){
if (tmp == col[j]){
i++;
}
}
col=tmp;
}

I've got it wrong: if it fails uniqueness, I don't want to increment i, I just want it to try another random #.

 

[DaveC426913]

[Edit: That Math.round() should be Math.floor() ]

 

[DaveC426913]

OK, this works, but it's ugly:

for (i=1;i<=6;i++){
tmp = Math.floor(Math.random()*14)+1;
for (j=1;j<i;j++){
if (tmp == col[j]){
tmp = Math.floor(Math.random()*14)+1;
j=0;
}
}
col=tmp;
}

 

[mwolf00]

<script type="text/JavaScript" language="JavaScript">

numStr = ""
for (x=1; x<=6; x++){
  do{
    tmp = Math.floor(Math.random()*14)+1;
    tmp = tmp + ","
  } while (numStr.indexOf(tmp) != -1)
  numStr = numStr + tmp
}
alert(numStr)


</script>

Programming today is a race between software engineers striving to build better and bigger idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning. - Rick Cook

 

[trollacious]

Here's a link to a similar one I answered not too long ago:

http://tek-tips.com/viewthread.cfm?qid=1206056

The code is flexible enough to adapt pretty easily to your situation.

Lee

 

[kaht]

This is kinda sexy - runs in only one loop. It'd be 3 lines if javascript had an inherent swap function, or if you could pop any element out of an array (not just the last):

<script type="text/javascript">

var arr = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen"]

var result = "";
var str = "";
var rnd = 0;

for (i = 0; i < 6; i++) {
   [gray]//generate the random number[/gray]
   rnd = Math.floor(Math.random() * arr.length);
   [gray]//swap random number with last element[/gray]
   str = arr[rnd];
   arr[rnd] = arr[arr.length - 1];
   arr[arr.length - 1] = str;
   [gray]//pop the last element[/gray]
   result += arr.pop() + "\n";
}

alert(result);

</script>

-kaht

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[trollacious]

Good one, kaht. I'm going to have to remember that algorithm in the future. #

Lee

 

[kaht]

thanks!

-kaht

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[DaveC426913]

Yeah, that last one's slick! Thanks y'all!

 

[kaht]

Got the loop condensed even more to only 2 lines (had do look up some array functions today and came across splice, don't even have to use pop this way):

<script type="text/javascript">

var arr = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen"]

var result = "";
var str = "";
var rnd = 0;

for (i = 0; i < 6; i++) {
   //generate the random number
   rnd = Math.floor(Math.random() * arr.length);
   result += arr.splice(rnd, 1) + "\n";
}

alert(result);

</script>

-kaht

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