Random shuffle of vector elements without repeating

5 次查看（过去 30 天）
Janell Lopez
Janell Lopez 2016-3-12
评论： Janell Lopez 2016-3-12
For my class, I have to create an anagram-type function that receives an input string, shuffles all the elements, and returns a new string of the shuffled letters. We are to use for loops and if statements; we can't use perms, randperm, or randsample. I have a good start on this:
outstr=zeros(size(instr));
for i=1:numel(instr)
outstr(randi([1,numel(instr)]))=instr(randi([1,numel(instr)]));
end
char(outstr)
My question is how to avoid repetition. Right now my function works, but it will repeat elements and thus leave some out. I'm thinking an if statement, to compare the randomly selected index to what has already been selected, but I can't pound it out yet. Any help is appreciated.

请先登录，再回答此问题。

回答（1 个）

Jan
Jan 2016-3-12
You can sort a vector of random values. The sorting index does not contain repetitions.
Did you search for a shuffle algorithm in the internet already? Look for "Knuth" and "Yates".
  1 个评论
Janell Lopez
Janell Lopez 2016-3-12
This is what I see for Yates:
function shuffle(array) {
var m = array.length, t, i;
// While there remain elements to shuffle…
while (m) {
// Pick a remaining element…
i = Math.floor(Math.random() * m--);
// And swap it with the current element.
t = array[m];
array[m] = array[i];
array[i] = t;
}
return array;
I'm not familiar with Javascript--what would the likenesses be for my instr and outstr? How can I divide up this code for a function with input/output arguments?
Thank you!

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by