How can I remove duplicates from ScoreBoard array? - c#

public void CheckForHighScore(){
finall = PlayerPrefs.GetInt("score");// taking score variable from another script to pass in ScoreBoard
for (int x = 0; x < highScores.Length; x++){
if (finall > highScoreValues[x]){
for (int y = highScores.Length - 1; y > x; y--) { //sorting
highScoreValues[y] = highScoreValues[y - 1];
}
highScoreValues[x] = finall;
DrawScores();
SaveScore();
PlayerPrefs.DeleteKey("score");
break;
}
}
}
void DrawScores() {
for (int x = 0; x < highScores.Length; x++) { // just adding score to string
highScores[x].text = highScoreValues[x].ToString();
}
}
Hey guys. How can I remove duplicates from ScoreBoard array? Tried myself to put this code below the sorting loop but actually nothing happens. I've also tried other methods but they don't work properly. Any help is appreciated.
/*for (int j = 1; j < x; j++)
{
if (highScoreValues[j] == highScoreValues[x])
break;
else
highScoreValues[x] = finall;
}*/

You can use linq.
If highscore is an object, you must override Equals and GetHashCode
public override bool Equals(object obj)
{
// Insert the Code to override
}
public override int GetHashCode()
{
// insert the Code to override
}
Be sure, that GetHashCode returns a unique integer for each object. For this way you can see more here: Correct way to override Equals() and GetHashCode()
If highScore is a primitives, you don't need to override the methods.
After you have unify highScore, you can use this:
var sorted = highScores.OrderByDescending(h => h).Distinct().ToArray();

List<*Insert type of score here*> cache = new List<*Insert type of score here*>();
for(int index = 0; index < highScores.Length; ++index)
{
if(cache.Contains(highScores[index]))
{
highScores.RemoveAt(index);
--index; // Every time you have to remove an item, it will slot the next item
// into that index and subtract 1 from highScores length. Thus you
// will have to decriment the index in order to check the item that
// gets pushed into that index of your highScore Array. You many
// need to check the syntax if highScores is not a List. But
// hopefully this helps :)
}
else
{
cache.Add(highScores[index]);
}
}
}
}

Related

Get the biggest value of an array

I have a textbox to write the position of an array and a textbox to write the value of that position. Every time I want to add a value and a position I click the button btnStoreValue
I created a function (CompareTwoNumbers) for another exercise that compares two numbers and returns the biggest
Using that function and avoiding the use of comparison characters like > and < I'm supposed to get the biggest value of the array
public partial class Form1 : ExerciseArray
{
int[] numbers = new int[10];
private int CompareTwoNumbers(int i, int j)
{
if (i < j)
{
return j;
}
return i;
}
private void btnBiggestValue_Click(object sender, EventArgs e)
{
//int n=1;
int counter = 0;
int highestPosition = CompareTwoNumbers(0, 1);
for(int i=0; i<10; i++){
//int j = CompareTwoNumbers(numbers[i], numbers[i+1])
//n = CompareTwoNumbers(numbers[n], numbers[i+1]
counter = CompareTwoNumbers(highestPosition, i);
}
txtBiggestValuePosition.Text= n.ToString();
txtBiggestValue.Text=numbers[n].ToString();
}
I've tried multiple things, using multiple variables, I tried to write it on paper to try to understand things better and I'm stuck. I don't know how is it possible to find that value using the function I created on the previous exercise (assuming the function I created is correct)
So, the core part of your question is that you want to know how to find the biggest number in an array using your helper function CompareTwoNumbers and then figure out what the value and position of the biggest number is.
Based on my understanding above, you have the framework almost set up correctly.
First off, CompareTwoNumbers should be updated to return a bool. Doing this will let you conditionally update your variables holding the biggest number value and position.
private int CompareTwoNumbers(int i, int j)
{
if (i < j)
{
return true;
}
return false;
}
To know what the largest value in an (unsorted) array is, you will need to iterate through every value. While doing so, you need to keep track of the value and position of the biggest value, only updating it when a bigger value is found.
private void btnBiggestValue_Click(object sender, EventArgs e)
{
// Store the bigget number's index and value
// We start with the first index and corresponding
// value to give us a starting point.
int biggestNumberIndex = 0;
int biggestNumber = numbers[0];
// Iterate through the array of numbers to find
// the biggest number and its index
for(int i=0; i<10; i++)
{
// If the current number is larger than the
// currently stored biggest number...
if(CompareTwoNumbers(biggestNumber, numbers[i])
{
// ...then update the value and index with
// the new biggest number.
biggestNumber = number[i];
biggestNumberIndex = i;
}
}
// Finally, update the text fields with
// the correct biggest value and biggest
// value position.
txtBiggestValuePosition.Text= biggestNumberIndex.ToString();
txtBiggestValue.Text=numbers[biggestNumberIndex].ToString();
}
This uses a Tuple to give you both the max index and max value from the same method:
public (int, int) FindMaxValue(int[] items)
{
int maxValue = items[0];
int maxIndex = 0;
for(int i=1;i<items.Length;i++)
{
if (items[i] > maxValue)
{
maxValue = items[i];
maxIndex = i;
}
}
return (maxIndex, maxValue);
}

C#: My Sorting Method/ Printing class does not print the first entry

I have implemented my own selection sort method that seems to be doing it's job for the most part; However, when I am printing files to an excel sheet the printer does not print the first item. I am unsure whether or not the sort method is the source of the problem. My test method for my sort method passes, which is why I am doubting that that is the source. My sort method is shown below. Does it have an error in the scope or order or operations? When I manually move through it on paper everything sorts properly.
public bool sortMaterial()
{
for (int i = 0; i < salesList.Count - 2; i++)
{
Sales curr = salesList[i];
Sales temp;
Sales min = curr;
int swap = 0;
for (int j = i + 1; j < salesList.Count; j++ )
{
temp = salesList[j];
if (String.Compare(temp.material, min.material) == -1)
{
min = temp;
swap = j;
}
}
salesList[i] = min;
salesList[swap] = curr;
}
return true;
}
A neat way to do custom sorting is by implementing the IComparer<T> interface:
public class SalesMaterialComparer : IComparer<Sales> {
public int Compare(Sales x, Sales y) {
return String.Compare(x.material, y.material);
}
}
You can pass your custom comparer to the LINQ OrderBy() method.
IEnumerable<Sales> salesList;
var myComparer = new SalesMaterialComparer();
var sorted = salesList.OrderBy(s => s, myComparer);

How to change this function to the recursive function

I have the following code that compares the node.Texto each both given node sets and then return one if they are equal otherwise zero. But my problem is that it just compare the first children because of nodes2.Nodes[ii] hence I know that it will not go forward more.
As I know if it was TreeNodeCollection it was easy to do recursive for each node and sub-node using foreach loop.
But here how I could change the code to the recursive version?
thanks in advance!
public int Compare_ChildNodes(TreeNode nodes1, TreeNode nodes2)
{
int length_children1 = nodes1.Nodes.Count;
int length_children2 = nodes2.Nodes.Count;
int result_int = 1;
if (length_children1 != length_children2)
{
result_int = 0;
}
else
{
for (int ii = 0; ii < length_children1; ii++)
{
if (nodes1.Nodes[ii].Text.Equals(nodes2.Nodes[ii].Text))
{
int ret = Compare_ChildNodes(nodes1.Nodes[ii], nodes2.Nodes[ii]);
result_int = ret;
}
else
{
result_int = 0;
}
}
}
return result_int;
}
I can't see any problems here. Calling Compare_ChildNodes with nodes1.Nodes[ii] and nodes2.Nodes[ii] does exactly the recursion you want.
I'd just suggest a little optimization ("early out") for your code:
public int Compare_ChildNodes(TreeNode nodes1, TreeNode nodes2)
{
int length_children1 = nodes1.Nodes.Count;
int length_children2 = nodes2.Nodes.Count;
int result_int = 1;
if (!nodes1.Text.Equals(nodes2.Text)) return 0; // not equal
if (length_children1 != length_children2) return 0; // not equal
return nodes1.Nodes.OfType<TreeNode>.Select((node, idx) =>
Compare_ChildNodes(node, nodes2.Nodes[idx]).Any(result => result == 0) ? 0 : 1;
}
I changed the comparison for the node's text to another recursion level so you can recurse using linq.
The linq Any method checks if any of the comparisons (in the Select method) returns 0 indicating that a child node collection is not equal.
The Select is called for each TreeNode in node1.Nodes and with it's index in that collection. So you can use this index to get the matching node from node2.Nodes and call Compare_ChildNodes for these two.
As soon as you find unequal (child-)nodes, you can return 0 and don't need to continue comparing the other nodes.
If you cannot use the linq statements (for Framework reasons or others), you can still use your for loop:
for (int idx = 0; idx < length_children1; idx++)
if (Compare_ChildNodes(nodes1.Nodes[idx], nodes2.Nodes[idx]) == 0)
return 0;
return 1;

C# Sorting Strings only on first letter

I'm trying to sort a list of strings in alphabetical order in C#. My code looks like this:
public static List<Result> sort(List<Result> listToSort)
{
int listSize = listToSort.Count;
for (int i = 0; i < listSize; i++)
{
for (int j = 0; j < listSize; j++)
{
if (listToSort[i].SN[0] < listToSort[j].SN[0])
{
Result tempValue = listToSort[j];
listToSort[j] = listToSort[i];
listToSort[i] = tempValue;
}
}
}
return listToSort;
}
But it's only sorting it based on the first letter of a string. In other words, if I have a list like this:
donald, abby, dave, bob, sam, pete
It will sort it like so:
abby, bob, donald, dave, pete, sam
One would expect 'dave' to come before 'donald'..
Any ideas?
Currently you are only sorting by the first letter that is why you are seeing this result. You can use Enumerable.OrderBy - LINQ
List<Result> sortedList = listToSort.OrderBy(r=> r.SN).ToList();
Or for your current code you can modify your check to:
if (string.Compare(listToSort[i].SN,listToSort[j].SN) < 0)
How about using LINQ for this:
return listToSort.OrderBy(report => report.SN)
I'm assuming your Report class has a string property you want the list to be sorted by?
EDIT
Didn't notice that you'd already specified the SN property, have amended my answer.
public static List<Result> sort(List<Result> listToSort)
{
return listToSort.OrderBy(x=>x.SN[0]).ToList();
}
You're only ever evaluating the first letter. Try using the traditional sorting method:
public static void Sort(List<Result> listToSort)
{
listToSort.Sort(new ResultComparator());
}
public class ResultComparator : IComparer<Result>
{
public int Compare(Result x, Result y)
{
if (x == null && y == null) return 0;
if (x == null) return 1;
if (y == null) return 0;
// compare based in SN
return string.Compare(x.SN, y.SN);
}
}
Take a look at this part:
for (int i = 0; i < listSize; i++)
{
for (int j = 0; j < listSize; j++)
{
if (listToSort[i].SN[0] < listToSort[j].SN[0])
{
You are
only comparing on SN[0]. If SN is a string then that explains your main result.
always using the same compare, whether i < j or i > j
Best thing to do is to use a built-in sort. Linq's OrderBy(lambda) is the easiest but it creates a new list. For an in-place sort, use List<T>.Sort(Comparer).
If you do have to do it yourself, look up a good sorting algorithm (wikipedia).
It was happened because of comparing character of the first string (listToSort[i].SN[0] => which produces the first character of your input). If you want to compare the string values, you should use string.Compare() method.
--SJ

comparing strings, one from an array other from an entered value

Basically comparing a string that is entered, and trying to get that position from the array.
If I initialize position to 0 then it returns the position zero of the array, if I initialize to 1 then it gives me the item in slot 1, so it's skipping the compare statement.
I also tried using (custStatus == cardStatus[i])
public static int discount(string []cardStatus, int []pDiscount, string custStatus)
{
int position= 0;
int discount;
for(int i = 0; i < 2; i++)
{
if (string.Equals(custStatus, cardStatus[i]))
position = i;
}
discount = pDiscount[position];
return discount;
}
With your code, there's no way to tell if position = 0 means custStatus was found in your cardStatus array or if no match was made at all and the default value is being used. I'd recommend either using a boolean matchFound variable or setting position = -1 and adding an extra if statement at the end either way. Either:
boolean matchFound = false;
...
if(matchFound)
{
discount = pDiscount[position];
}
or else
int position = -1;
...
if(position >= 0)
{
discount = pDiscount[position];
}
Give this a try:
public static int discount(string[] cardStatus, int[] pDiscount, string custStatus) {
var position = Array.IndexOf(cardStatus, custStatus);
return (position == -1) ? -1 : pDiscount[position];
}
public static int discount(string []cardStatus, int []pDiscount, string custStatus)
{
for(int i = 0; i < Math.Min(cardStatus.Length, pDiscount.Length); i++)
{
if (string.Equals(custStatus, cardStatus[i]))
{
return pDiscount[i];
}
}
return -1;
}
Don't be afraid to return directly from FOR-loop, it is old-school that teaches to have only one return point from method. You can have as many returns as it helps you to keep your code clean and easy to read.
And perhaps it would be better to use the following expression in for-loop as it will guard you from possible different lengths of arrays:
for (int i = 0; i < Math.Min(cardStatus.Length, pDiscount.Length; i++)
This looks ok, even though this is somewhat more straightforward:
for(int i = 0; i < cardStatus.Length; i++)
{
if (custStatus == cardStatus[i])
{
position = i;
break;
}
}
Given your question it appears to be the case that all cardStatus[i] match custStatus - did you check the input?
Also given your code what happens if there is no match? Currently you would return pDiscount[0] - that doesn't seem to be correct.

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