koobas.hobune.stream
Check times a value is next to the same value in an array
Lets say I have this array on C#:
int myList = {1,4,6,8,3,3,3,3,8,9,0}
I want to know if a value (lets say from 0-9) is next to itself in the list and how many times. In this case, the value 3 is next to itself and it has 4 repetitions. If I have a list {0,1,2,3,4,5,5,6,7} the value 5 is next to itself and has 2 repetitions.
Repetitions have a limit of 5. No value can be repeated more than 5 times. The far I went is making if statements, but I know there's a better way of doing it.
You need more constrains or it will break. For instance, your first example, 3 is next to itself, ok. What about the last one? Isn't it next to 8? Also, what is next? Is it before or after?
You could use a function like this:
public int GetRepetitions(int[] myList, int value)
{
int repetitions = 0;
for (int i = 0; i < myList.Length; i++)
{
if ((myList[i] == value) && ((i == 0 ? false : myList[i - 1] == value) ||
(i == myList.Length - 1 ? false : myList[i+1] == value)))
{
repetitions++;
}
}
return repetitions;
}
In case you haven't seen it, the a ? b : c operator just means if a then b else c.
Edit: hehe, too slow, either will work.
This doesn't work well if the list is {1,2,3,3,4,5,6,3,3,3} it prints 5 when it should print or 2 or 3.
Nevertheless I think I can change to make it work as I need! THAN$$anonymous$$ YOU!!!
Can you explain me better the if? it checks the previous value if not the first and the next value if not the last?
The ? : thing is called a ternary operator. Basically it's just an inline if then else statement, so if the first part before the question mark is true then you use the statement on the left of the colon, otherwise you use the statement on the right of the colon if it's false.
basic forloop will do
using System;
void Start(){
int[] myArray = new int[]{1,1,1,3,3,3,3};
Debug.Log(howManyRepetitionsAfterFirstOccurance(ref myArray, 3) );
}
int howManyRepetitionsAfterFirstOccurance(ref int[] array2Inspect, int value2Check){ //pass array by reference (don't copy it over, just point your finger at the one to work with
startingPos = Array.IndexOf(array2Inspect, value2Check) //get the index of the first occurance of the number you need
int repetitions = 0;
for(int i = startingPos; i < array2Inspect.Length; i++){ //see if its present once or more in the array
int value_at_cell = array2Inspect[ i ];
if (startingPos == -1 || value_at_cell != value2Check) break;
repetitions++;
}
return repetitions;
}
Thanks! That should work in the case the list isn't something like {3,1,2,3,3,3,3,3} how do you fix that?
To "fix" that you'd first need to design how you want it to work in that case. Return the length of the longest set, last set, first found, length of all sets combined ...
return 0 if the startingPos is not -1
iterate through the array starting from the startingPos and keep bumping the number of repetitions. If suddenly the value does not equal to the one you wanted, then the repetition has ended.
Store this accumulated result in a biggestRepetitions if it is smaller than the current repetitions. reset repetitions back to zero keep going until you reach the end of the array and return biggestRepetitions.
Already answered, but i'll just leave this here for fun :)
void countNumber(int[] array, int value, out int longest, out int cumulative, out int first, out int last)
{
cumulative = longest = first = last = 0;
int lastIndex = array.Length - 1;
int currentStreak = 1;
bool wasMatch = false;
for(int i = 0; i <= lastIndex; i++)
{
bool isMatch = array[i] == value;
if (wasMatch)
{
if (isMatch)
{
currentStreak++;
}
bool endOfStreak = !isMatch || i == lastIndex;
if (endOfStreak && currentStreak > 1)
{
if (currentStreak > longest) longest = currentStreak;
if (first == 0) first = currentStreak;
last = currentStreak;
cumulative += currentStreak;
currentStreak = 1;
}
}
wasMatch = isMatch;
}
}
I have this solution which can pick the consecutive repeated elements (even if they are repeated itself too).
e.g., cases like:
{ 1, 4, 3, 6, 6, 8, 3, 3, 3, 3, 8, 9, 0 }; // Here 6 and 3 are repeated
{ 1, 4, 3, 3, 6, 6, 8, 3, 3, 3, 3, 8, 9, 0 }; // Here 6 repeated once and 3 repeated twice
Sample Code:
int[] myList = new int[] { 1, 4, 3, 3, 6, 6, 8, 3, 3, 3, 3, 8, 9, 0 };
Dictionary<int, List<int>> groupDict = new Dictionary<int, List<int>>();
string characters = string.Join("", myList.ToArray());
for (int i = 0; i < characters.Length; i++)
{
int cInt = int.Parse(characters[i].ToString());
MatchCollection mColl = Regex.Matches(characters.Substring(i), "^" + characters[i] + "{2,}");
if (mColl.Count > 0)
{
if (!groupDict.Keys.Contains(cInt))
{
groupDict.Add(cInt, new List<int>());
}
groupDict[cInt].Add(mColl[0].Length);
i += mColl[0].Length - 1;
}
}
}
For first case it will show you: (in-memory result)
6 -> 2
3 -> 4
For second case it will show you: (in-memory result)
6 -> 2
3 -> 2, 4
Hope it is useful for you.
