namikaze:

Another way to express your solution without the recursion would be;

function shuffle(Array arr) 
{
   HashSet seenIndices = new HashSet()
   Array result = new Array()
   for (int i in 0 to arr.length())
   {
      rand_idx = random num in range(0, arr.length())
      while (seenIndices.contains(rand_idx)
      {
        rand_idx = random num in range(0, arr.length())
      }
      result.add(arr[rand_idx])
      seenIndices.add(rand_idx)
    }
  return result;
}

This I think follows the same idea, but would still depend on the random function, so not recommended.

That's the thing about programming if your solution is not optimised you would know. So there is always room for growth till you move to the next thing.

The randrange you used in python should also depend on random but it's abstracted though am not sure of this.

function shuffle( arr ) {
Const seenArray = [ ]
Const shuffledArray = [ ]
for ( i=0,i<arr.length-1,i++) {
let randomIndex = math.floor( math.random( )
*arr.length)
If (!seenArray.include(randomIndex)) {
shuffledArray [ randomIndex] = arr[i]
seenArray[i] = randomIndex
} else {
for ( k=0,k<arr.length,k++) {
If ( shuffledArray[k] == null) {
shuffledArray[k] = arr[i]
break;
}
}

}


}
Return shuffledArray;
}

namikaze:

Another way to express your solution without the recursion would be;

function shuffle(Array arr) 
{
   HashSet seenIndices = new HashSet()
   Array result = new Array()
   for (int i in 0 to arr.length())
   {
      rand_idx = random num in range(0, arr.length())
      while (seenIndices.contains(rand_idx)
      {
        rand_idx = random num in range(0, arr.length())
      }
      result.add(arr[rand_idx])
      seenIndices.add(rand_idx)
    }
  return result;
}

This I think follows the same idea, but would still depend on the random function, so not recommended.

I think there is a chance this might go into infinite loop

Deicide:
Cause it's one of the best programming languages ever, honestly you should try it.

Everybody that has written it has sworn by it, but I don't know what Project to use it for, what do you use it for or just learning, is it straight forward ?

chukwuebuka65:
function shuffle( arr ) { Const seenArray = [ ] Const shuffledArray = [ ] for ( i=0,i<arr.length-1,i++) { let randomIndex = math.floor( math.random( ) *arr.length) If (!seenArray.include(randomIndex)) { shuffledArray [ randomIndex] = arr[i] seenArray[i] = randomIndex } else { for ( k=0,k<arr.length,k++) { If ( shuffledArray[k] == null) { shuffledArray[k] = arr[i] break; } }
}

} Return shuffledArray; }

js things point. can someone implement this in c or typescript

qtguru:


Everybody that has written it has sworn by it, but I don't know what Project to use it for, what do you use it for or just learning, is it straight forward ?

You can actually use it for anything. To be honest I was left with go or rust which to use for Sys admin stuff and I just picked rust all I use it for now is to write some CMD tool to solve admin task. And since it's cross platform it's also a plus though I still use go sometimes for that.

Though I might no be using the full power but it suites my use case just fine.

Deicide:
That's the thing about programming if your solution is not optimised you would know. So there is always room for growth till you move to the next thing.

The randrange you used in python should also depend on random but it's abstracted though am not sure of this.

No it's not like that. In my case, any value returned by the random() function would be used. In your case any value wouldn't do, it would have to return a new value not inside of the HashSet.

chukwuebuka65:


I think there is a chance this might go into infinite loop

I know, this is not my solution, I was trying to remove the recursion from op's solution, mine's on the first page of the thread.

chukwuebuka65:
function shuffle( arr ) {
Const seenArray = [ ]
Const shuffledArray = [ ]
for ( i=0,i<arr.length-1,i++) {
let randomIndex = math.floor( math.random( )
*arr.length)
If (!seenArray.include(randomIndex)) {
shuffledArray [ randomIndex] = arr[i]
seenArray[i] = randomIndex
} else {
for ( k=0,k<arr.length,k++) {
If ( shuffledArray[k] == null) {
shuffledArray[k] = arr[i]
break;
}
}

}


}
Return shuffledArray;
}

God of bugs
In all seriousness lots of syntax errors and even after fixing the errors does not give the desired output. I bet you typed it on nairaland.

namikaze:

God of bugs
In all seriousness lots of syntax errors and even after fixing the errors does not give the desired output. I bet you typed it on nairaland.

He should have used typescript
Seun need to fix code formatting on Nairaland even if it's only for this section, I mean see Quora see Reddit.

namikaze:

God of bugs
In all seriousness lots of syntax errors and even after fixing the errors does not give the desired output. I bet you typed it on nairaland.

Yea, but I think u didnt get the concept. If you get the concept u can fix it.

Deicide:
Was able to come up with this using rust.

static mut TEMP_V: Vec<i32> = Vec::new();
lazy_static! { 
    static ref TEMP_SET: HashSet<i32> = {
    let mut is_in = HashSet::new();
    is_in
};
fn shuffel(nums: &Vec<i32>, count: usize) -> &'static Vec<i32> {
    unsafe {
        while TEMP_V.len() <= nums.len() {
            let rval: u32 = rand::random::<u32>() % nums.len() as u32;
            if TEMP_SET.contains(&nums[rval as usize]) {
                if count <= 0 {
                    break;
                }
                shuffel(&nums, count - 1);
            } else {
                TEMP_SET.insert(nums[rval as usize]);
                TEMP_V.push(nums[rval as usize]);
            }
        }
        return &TEMP_V;
    }
}

is this what you call array?

namikaze:

from random import randrange

def shuffle(arr):
  for i in range(len(arr)):
    rand_idx = randrange(len(arr))
    arr[rand_idx], arr[i] = arr[i], arr[rand_idx]
  return arr
 
arr = [1,2,3,4,5]
print(shuffle(arr))

Using your python logic in rust, code translate to

fn shuffle(nums: &mut Vec<i32> ) -> Vec<i32> {
    let mut rng = rand::thread_rng();
    for num in 0..nums.len() {
        let x: u32 = rng.gen_range(0..nums.len() as u32);
        nums.swap(num, x as usize);
    }
    return nums.to_vec();
}

This is fucking fast, cause it's using multiple thread and random results are cached

Now I can finally rest and watch the sun set on a great universe

Xedmark:


is this what you call array?

Yes, vectors are dynamic array

chukwuebuka65:
function shuffle( arr ) {
Const seenArray = [ ]
Const shuffledArray = [ ]
for ( i=0,i<arr.length-1,i++) {
let randomIndex = math.floor( math.random( )
*arr.length)
If (!seenArray.include(randomIndex)) {
shuffledArray [ randomIndex] = arr[i]
seenArray[i] = randomIndex
} else {
for ( k=0,k<arr.length,k++) {
If ( shuffledArray[k] == null) {
shuffledArray[k] = arr[i]
break;
}
}

}


}
Return shuffledArray;
}

Your code still has bugs after testing... it will be impressive to know u wrote it here on nairaland even before testing...

sometimes it prints out empty in the array
Nairaland reduced the quality of the image

chukwuebuka65:



Yea, but I think u didnt get the concept. If you get the concept u can fix it.

What concept? unless you want me to debug your code lol.

Deicide:


Using your python logic in rust, code translate to

fn shuffle(nums: &mut Vec<i32> ) -> Vec<i32> {
    let mut rng = rand::thread_rng();
    for num in 0..nums.len() {
        let x: u32 = rng.gen_range(0..nums.len() as u32);
        nums.swap(num, x as usize);
    }
    return nums.to_vec();
}

This is fucking fast, cause it's using multiple thread and random results are cached

Now I can finally rest and watch the sun set on a great universe

I see you rustecean, flexing Rust features anyhow
You can't rest o, it's night here already

LET ME CONTRIBUTE WITH JS

explanation.

I am using while loop.

while the length of shuffled array is not equal to given array the loop keeps running.

now each time loops run a random value from given array is produced.

now we push that value to the shuffled array provided it doesn't exist there previously,

This way we get unique random values in shuffled array.

code can be shortened further with ternary operators... for readability lets go with IFS
i know it's neat.



function shuffle(arr) {
const shuffled = []

while(shuffled.length!==arr.length){
let randVal = Math.floor(Math.random()*arr.length)
if (!shuffled.includes(arr[randVal])) {

shuffled.push(arr[randVal]);
}

if (shuffled.length===arr.length)
return shuffled
}
}
shuffle(["a", "b", "c", "d", "e","g","h","i"]);

chukwuebuka65:
function shuffle( arr ) {
Const seenArray = [ ]
Const shuffledArray = [ ]
for ( i=0,i<arr.length-1,i++) {
let randomIndex = math.floor( math.random( )
*arr.length)
If (!seenArray.include(randomIndex)) {
shuffledArray [ randomIndex] = arr[i]
seenArray[i] = randomIndex
} else {
for ( k=0,k<arr.length,k++) {
If ( shuffledArray[k] == null) {
shuffledArray[k] = arr[i]
break;
}
}

}


}
Return shuffledArray;
}

This code is full of bed bugs and caterpillars
Too many syntax errors ranging from ";" to "mixture of capital and small letters "

const number = [23. 474, 74, 37, 27]

function shuffleArray(array) {

return array.sort( () => Math.random() - 0.5 );

}

console.log(shuffleArray(number))

GREATIGBOMAN:
LET ME CONTRIBUTE WITH JS

explanation.

I am using while loop.

while the length of shuffled array is not equal to given array the loop keeps running.

now each time loops run a random value from given array is produced.

now we push that value to the shuffled array provided it doesn't exist there previously,

This way we get unique random values in shuffled array.

code can be shortened further with ternary operators... for readability lets go with IFS
i know it's neat.



function shuffle(arr) {
const shuffled = []

while(shuffled.length!==arr.length){
let randVal = Math.floor(Math.random()*arr.length)
if (!shuffled.includes(arr[randVal])) {

shuffled.push(arr[randVal]);
}

if (shuffled.length===arr.length)
return shuffled
}
}
shuffle(["a", "b", "c", "d", "e","g","h","i"]);

me likey but it's too much code

Csami:


me likey but it's too much code

How too much code lol

It's actually short lol

Csami:


This code is full of bed bugs and caterpillars
Too many syntax errors ranging from ";" to "mixture of capital and small letters "

const number = [23. 474, 74, 37, 27]

function shuffleArray(array) {

return array.sort( () => Math.random() - 0.5 );

}

console.log(shuffleArray(number))

Nice.... but your solution is quite popular on google

Csami:


This code is full of bed bugs and caterpillars
Too many syntax errors ranging from ";" to "mixture of capital and small letters "

const number = [23. 474, 74, 37, 27]

function shuffleArray(array) {

return array.sort( () => Math.random() - 0.5 );


}

console.log(shuffleArray(number))

I know because I wrote it off-hand here on nairaland while at the market. But you should try to avoid abstractions in your algorithms where necessary so we can determine the time and space complexity . You should have used array.sort().