Question 398851 in Javascript Question posted in
A very good W3school tutorial can be found here.

Javascript – Ideas on how to dynamically create a Golf Draw table and randomly allocate players to it

I help organise a ‘golf society’ and each week we make a draw to decide who is playing with who, by pulling numbers out of a’ hat’. I am in the process of building a website (app) and want to add a draw function.

The web app is written in NextJS and uses Supabase for auth and member / event data.

So the parameters are:

Total numbers: 4, (not 5), 6 …… up to 32

slot size: 4 or 3 (i.e. preferably 4 i.e teams of 2 x 2 players but can be 3. (How 3 players work is a golf issue not a coding issue)

Table order: The ‘3 balls’ need to be at the top of the table.

My data: Is drawn from Supabase. The query filters on a date and only picks players who have said they will play. A function then adds a random number to each of the players. The final data is an array of ‘members’. Each member being an object including {name: bill, rnd: 0.5565789}

Logic

If the leftOver (see code below) is 3, then I need 1 x 3 players in a row (each with a blank field under column 4) and the rest rows in 4 filled columns.

If the leftOver is 2, then I need 2 rows x 3 columns (each with a blank field under column 4) and the rest in 4 filled columns.

If the leftOver is 1, then I need 3 rows x 3 columns (each with a blank field under column 4) and the rest in 4 filled columns.

If the leftOver is 0, then all rows are all 4 filled columns.

Initial code below. I need to dynamically fill a table with rows of 3 or 4 filled by member.names using the random number to order them.

I am sure I can do it (in a long laborious and messy way) but I am looking for a code efficient solution and hope someone can help.

Thank you

My baseline code is:

const date = await getLatestDate()
        if (!date) { throw Error }

        const members = await getMembers(date)
        if (!members) { throw Error }

        const playingMembers: Member[] = members.filter(
            (members) => members.playing == true)

        const numberPlaying: number = playingMembers.length

        // CODE: won't work with <3 or 5

        playingMembers.forEach(element => {
            element.rnd = Math.random()
        })

        const leftOver = numberPlaying % 4
Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Thank you, Barry.

    Here is my solution. If anyone can imporve with coding best practice I would love to hear from you.

    export async function getDrawData() {

try { //TOAST MOST OF THESES ERRORS

    const date = await getLatestDate()
    if (!date) throw Error('Could not find latest date. Please note: draw/actions.tsx')

    const members = await getMembers(date)
    if (!members) throw Error('Could not get list of members from database. Please note: draw/actions.tsx')

    const playingMembers: Member[] = members.filter(
        (members) => members.playing == true)

    const numberPlaying: number = playingMembers.length

    if (numberPlaying == 5 || numberPlaying <= 3) {
        throw Error('Could not get list of members from database. Please note: draw/actions.tsx')
        ///   TOAST ?
    }

    playingMembers.forEach(element => {
        element.rnd = Math.random()
    })

    const dummyMember: Member = {
        id: "none",
        name: 'Pick a Middleman',
        admin: false,
        active: false,
        date: "none",
        playing: true,
        dining: false,
        buggy: false,
        loggedUser: {
            loggedID: "none",
            loggedName: " ",
            loggedisAdmin: false,
        },
        rnd: 0
    }

    const leftOver = numberPlaying % 4
    //console.log('Left over in draw: ', leftOver)
    switch (leftOver) {
        case 1:
            //code i.e. 9, 13 etc
            // 3 groups of 3 
            playingMembers.splice(3, 0, dummyMember)
            playingMembers.splice(7, 0, dummyMember)
            playingMembers.splice(11, 0, dummyMember)
            break
        case 2:
            // code i.e 6, 10 etc
            // 2 groups of 3
            playingMembers.splice(3, 0, dummyMember)
            playingMembers.splice(7, 0, dummyMember)
            break
        case 3:
            // code i.e 7, 11 etc
            // 1 groups of 3
            playingMembers.splice(3, 0, dummyMember)
            break
        default: // i.e. 4, 8 etc 
        // no change to playingMembers
        // Do I need default ?
    }

    const numberCompetitors: number = playingMembers.length
    const leftOverCompetitors = numberCompetitors % 4
    if (leftOverCompetitors > 0) {  // double check that after adding blanks, competitors are divisible by 4
        console.log('Cannot make draw table.  leftOverCompetitors in draw actions.tsx =: ', leftOverCompetitors)
        throw Error('Something went wrong creating draw.   Please note: draw/actions.tsx')
    }

    let slots: slots = []

    for (let i = 0; i < (numberCompetitors / 4); i++) {
        const slot: slot = playingMembers.slice(i * 4, (i * 4) + 4)
        slots.push(slot)
    }
    return slots
} catch {
    return null
}

    }


  2. 0

    The following code will help you calculate the number of 3 and 4 in C.

    #include <stdio.h>  


void verifyAndPrintCombination(int num) {  
    int fours = 0;  
    int threes = 0;  
    int remainder = 0;  

    fours = num / 4;  
    remainder = num % 4;  
      
        if (remainder == 1) {  
         
            threes=3; 
            fours=(num-threes*3)/4;
          
        } else if (remainder == 2) {  
        
            threes = 2;
            fours=(num-threes*3)/4;  
  
        } else if (remainder == 3) {  
     
            threes =1;  
        }  
        

    if (fours * 4 + threes * 3 == num&&fours>=0) {  
        printf("%d can be composed of %d four and %d three. n", num, fours, threes);  
    } else {  
        printf("%d cannot be composed with four and three . n", num);  
    }  
}  

int main() {  
    int number;  

    printf("input a number greater than 3:");  
    scanf("%d", &number);  

    if (number < 3) {  
        printf("input a number greater than 3:n");   
    }  

    verifyAndPrintCombination(number);  

    return 0;  
}

    My English is poor, so it is hard for me to write comments.(Translation is tedious)
    The max value of number three is 3, You only need to discuss four scenarios.
    I can just help you with the core part of the requirement because i am not good in java(and i am too lazy to learn right now ,ditto), I believe you can refine the rest of the code.

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