Calculate statistical distributions from a column in a datatable - vb.net

Question

I don't know if there is a specific method in VB.Net to calculate the statistical distribution from an array of values like the formula Frequency() in Excel. If not what is the easiest and fastest way of doing the same thing ?
For example I've a DataTable with my values in a Column called "Cement Deviation" :
Column Deviation
0
14
11
2
6
1
16
14
5
21
The bands in which I want to know the frequency of these values are :
From minValue To -50 by Step of 10
From -50 To -10 by Step of 5
From -10 To -5 by Step of 1
From -5 To -1 by Step of 0.5
From -1 To -0.5 by Step of 0.1
From -0.5 To -0.1 by Step of 0.05
From -0.1 To 0.1 by Step of 0.01
From 0.1 To 0.5 by Step of 0.05
From 0.5 To 1 by Step of 0.1
From 1 To 5 by Step of 0.5
From 5 To 10 by Step of 1
From 10 To 50 by Step of 5
From 50 To maxValue by Step of 10
Can someone help me with it?
Thanks

Answer 1

I don't know how you calculate it since my experiences with statistical distribution is limited and you haven't mentioned the way you want to calculate it.
However, this does at least compile:
Dim stat(2) As Integer
For Each row As DataRow In gridView.Rows
Dim cementDeviation = row.Field(Of Int32)("Cement Deviation")
Select Case cementDeviation
Case 0 To 10
stat(0) += 1
Case 10 To 20
stat(1) += 1
End Select
Next
In general there's nothing bad in looping the DataRows to calculate the values. But you should set OPTION STRICT to on, then your code would not compile because row("Cement Deviation") is an object not integer. The good thing is that you are forced to use the correct types which prevents from nasty runtime errors.
Edit Here is an example how you could use dynamic ranges and count each class with LINQ. I have used a DataTable to store the min- and max-values but you could also use a different in-memory collection like List(Of CustomClass) or even better - the database.
You can also simply loop the table but you wanted to see a different approach. I like LINQ since it can reduce complexitiy and increase readability:
The range table with sample data:
Dim rangeTable = New DataTable()
rangeTable.Columns.Add("Min", GetType(Int32))
rangeTable.Columns.Add("Max", GetType(Int32))
For i = 0 To 90 Step 10
rangeTable.Rows.Add(i, i + 10)
Next
A single LINQ query to calculate all occurences for every range even ordered descending:
Dim stats =
From rangeRow In rangeTable
Let min = rangeRow.Field(Of Int32)("Min")
Let max = rangeRow.Field(Of Int32)("Max")
Select StatsInfo = New With {
.Min = min, .Max = max,
.Count = (From devRow In devTable
Let cementDeviation = devRow.Field(Of Int32)("Cement Deviation")
Where cementDeviation >= min AndAlso cementDeviation <= max).Count()
}
Order By StatsInfo.Count Descending
Output the result:
For Each stat In stats
Console.WriteLine("Min: {0} Max: {1} Count: {2}", stat.Min, stat.Max, stat.Count)
Next
Note that i've renamed your DataTable to devTable since gridView is not a good name.