如何从包含相同数字的数组中获取所有索引值？

Question

copyarray = yAxisdata.slice(0);  
length=yAxisdata.length;   
for (k = 0; k <length-1; k++)
{ 
     maxvalue = copyarray[k];
     indexvalue = yAxisdata.indexOf(maxvalue);
}

I am trying to find the index value of the data from array who's contain 800 data approximately and it is also contain lots of same value.

Above codes are used to get the index value of all the elements which is available inside the array. but the problem is if array have a multiple same value at that time this code shows only index of first value and skip the same values in array and show the index of the other value.

Answer 1

I'm not 100% familiar with javascript but i think below will do the trick

copyarray = yAxisdata.slice(0);  
length=yAxisdata.length;  
var result;
var maxvalue = 0;
var counter;

for (k = 0; k <length-1; k++)
{ 
    maxvalue = copyarray[k];
    result = [];
    counter = 0;

    for(x = 0; x < length -1; x++)
    {
        if(copyarray[x] == maxvalue)
        {
            result[counter] = x;
            counter++;
        }
    }
}

The C# version would be

int[] copyarray = yAxisdata.Select(ch => ch - '0').ToArray();

List<int> result = new List<int>();
int maxvalue = 0; 

for (int k = 0; k < copyarray.Count() - 1; k++)
{
    maxvalue = copyarray[k];
    
    // Alternative code
    // result = copyarray.Select((value, index) => new { value, index }).Where((a) => a.value == maxvalue).Select((a) => a.index).ToList();
    result = new List<int>();

    for(x = 0; x < copyarray.Count() - 1; x++)
    {
        if (copyarray[x] == maxvalue)
        {
            result.Add(x);
        }
    }
}

The result variable is now an array with all the indexes containing the maxvalue