I want to calculate variance of a col in my datatable object. If i apply datatable.compute(Var(...)), i gives a negative result. Variance can't be negative. And it I just apply it to half of the data, it works fine. Does datatable.compute has a limited capacity?
View 7 Replieshow i'd solve for variance and Std. deviation. the project is meant to record housing prices, put them in a list box, and then compute these calculations
Public Class Form1
Dim intclicks As Integer = 0
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
[code]....
How can I calculate standard deviation and variance of a field in my database by using OleDb and SQL language in vb 2010. I used VARIANCE and STDDVE and VAR_SAMP but they are undefined. There is other function for do this or there is any way to define this kind of SQL functions to
OleDb?
I am trying to convert the following code for the variance calculation
public static double Variance(this IEnumerable<double> source){
double avg = source.Average();
double d = source.Aggregate(0.0,
(total, next) => total += Math.Pow(next - avg, 2));
return d / (source.Count() - 1);
}
Described on CodeProject into corresponded VB.NET lambda expression syntax, but I am stuck in the conversion of Aggregate function. How can I implement that code in VB.NET?
I need to round the result from compute.8/19, how can i round this result to two decimal.Is there any symbol i can use for compute function to recognize the rounding format, because not must be two decimal,sometime may one or in integer?
View 3 Repliesthis function enables you to calculate a full arithmetic calculation , as 5*(3+2)+6 , but : it's limited with (+,-,*,/) signs . is there any way to add a support for the another signs (like : !,sin,cos,tan,root,^,log and another signs) to give the user the ability to calculate a full calculation including the other signs which cannot be calculated within the compute.datatable function ?
View 2 RepliesI do have the following problem extracting records from a datatable, based on date.
I am using Datatable.compute to sum the relevant rows, at least I'm trying to!
CrTot is a variable of type double
BankTrans is a datatable
dteRecDte is a datetimepicker component
CrTot = BankTrans.Compute("sum(bank_amount)",
"bank_amount > 0 And date_bank_reconciled <="
& dteRecDte.Value.Date)
doing the sum calculation on it's own works properly. I now need to check that the date of the "date_bank_reconciled" field is less than or equal to the value of the date entered in the datetimepicker "dteRecDte.Value.Date", so that only rows with a date either less than or the same as that in the datetimepciker are returned.
I have an app that contains a DataTable that I must summarize. In that table is a Status column (also the index order) and I want to write a loop in which I compute the count for each status. So I wrote my loop and tried to use the compute function of the Datatable class, but I cannot get it working due to some constraints - specifically this...
[Code]....
You can see what I am doing here is grabbing the string value of the Status column, and then trying to get a count of how many records have that Status. My ultimate goal was to cycle the Table and count each time the status changes. But the error I get has to do with where I store the Status in a String, and then issue the second parameter on the Compute function which contains a variable (sumString) and this is where Compute is crashing - and of course, I can see why - my Status is not literal and thus not in quotes.
Generally speaking, is there any way to manage this kind of thing? In my (very) old FoxPro days one would use a macro such as "Status = &sumString" and VFP would translate sumString to its literal. I have never discovered a way to do that in .NET.
I need help with this line of code: Me.avgsalespricetxt.Text = Me.dtsold.Compute("AVG(Convert([Selling Price]),'System.Int32'))")
Here is all the code i have so far, I need to Average a column in my datatable from what i have read "Compute method supports expressions and they support CONVERT function that you could use inside of the expression."
[Code]...
I am using datatable.comput to calculate the avg of a data column. The data column's datatype = integer, so it returns a integer avg value as well. Can i make it to return double value?
View 3 RepliesI have a datatable and I apply a filter to the defaultview.rowfilter property of that datatable. If I then loop through the rows collection of the datatable, will I only be able to see those rows that the filter applies to, or will it loop through all the rows?
View 6 Repliesi have a datatable with some data, i need to select some of the data, and put that data in a new datatable.
View 1 RepliesI have a datatable with 2 columns named TimeStamp and value. After I populate the table with rows, I am using the table's compute method to get the max value like this....
MyTable.Compute("MAX(value)", Nothing)
Is there is a way to get the row (or more specifically the TimeStamp value) where the max was found?
I import my records into dataset1.table(0) I have invoice line items in dataset1 I want the total of all line items for a specific invoice# So I get SUM(col1 * col2) **WHERE invoice# = StrVarInvoice#?
For Each dataRow As DataRow In DataSet1.Tables(1).Rows
netamt = DataSet1.Tables(0).Compute("SUM(unitprce * quantity)", String.Empty)
Next
'My Try but is there a better way?? ? Do I have to loop through all records?
For Each dataRow1 As DataRow In DataSet1.Tables(1).Rows
If dataRow("invoice#") = StrVarInoivce# Then
netamt = DataSet1.Tables(0).Compute("SUM(unitprce * quantity)", String.Empty)
totamt = totamt + netamt
Next
I have a column: {2,2,null}. If i use datatable.compute to compute the avg of this column, will it return 2 or 1.66? In another word, will this function ignore the null value?
View 4 RepliesIn the below code, I create a DataTable and filter it. When I use filter1, everything works as expected.When I use filter2, everything works as expected only if the SubsectionAmount variable is less than 10. As soon as I set SubsectionAmount=10, the dr2 array returns Nothing.I can't find what is wrong. Here is the code:
Imports System.Data
Partial Class FilterTest
Inherits System.Web.UI.Page[code]..
I want to filter the data that's being displayed to my datagrid once I click the combobox and select a specific value,the selected value will be the item to filter the data that I needed to be displayed in the datagrid.. I'm using a datatable,a combobox and a datagrid..here's my code
Private Sub cboView_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cboView.Click
dt = New DataTable
sda = New SqlDataAdapter("SELECT DISTINCT KPIPOSTCODE FROM KKPIGROUP", sqlcon)
sda.Fill(dt)
[code].....
[code]When I call da.fill I am inserting all records from my query. I was then hoping to filter them to display only those where the GroupingID is equal to 0. When I run the above code. I am presented with all the data, the filter did not work. Please can you tell me how to get this working correctly.
View 1 RepliesI need filter for multiple values on one column using the DataTable.Select method.
Dim totalFatal As Integer =
m_DataSet.Tables("tblAccidentNonMotorist").Select(String.Format("[AccidentNumber] = '{0}' AND CONTAINS([InjuryClass], '"01" OR "02" OR "03"'", accidentNumber)).Length
[code].....
I am writing part of a function that tries to search for a username in a list in a rather broad way (last resort). It seems that LIKE does not like trying to match only the first and last characters.
strCriteria = "somename"
drFilter = tblUsers.Select("User LIKE '" & Strings.Left(strCriteria, 1) & "%" & Strings.Right(strCriteria, 1) & "'")
[code]....
I have a datatable called dt which includes a column called type.I have a string array called typestringarray with about 15 members
I want to create a new datatable from the rows where type is a member of typestringarray[code]...
Is there anyway to filter a DefaultView with a LIKE-type operator as in MySQL?I want to be able to make it so that in my program, a person can type in a textbox and as they type, the list is refiltered based on what is typed, but I want it to match anything in the string of text, not just starting from the beginning or an exact match.
View 5 RepliesWhat i am doing is to enable a user to specify in a combobox on a form a threshold (integer). On a button click the code steps through a datatable until the cumilative value of a field in the records row are equal or dont exceed the figure specified. It then selects these rows and presents them in a datgridview in another form. This all works just fine.
What i am struggling with is undertaking a sort on another field before it starts the filter part. It appears to revert to the default order. Here is my
If ComboBox1.Text = "Co2 saving in tonnes" Then
Dim table As New DataTable
Dim limit As Integer = ComboBox2.Text ' Your threshold
[Code].....
I have a select statement and it will go to a datatable object, I would like to do the following
textbox1.text=datatable(first field value)
textbox2.text=datatable(second field value)
textbox3.text=datatable(third field value)
I have a datatable loaded from a database. I bind the datatable to a gridview on page_load. Now I want to filter the gridview by a user selection so I made a checkboxlist and wrote some code as follow at CheckBoxList1_SelectedIndexChanged
[Code]...
With this code above, it can filter if there is only one selection on the checkboxlist. I try to loop the checkboxlist myself but always ended up in errors. Hope someone can help me out to make this work.
Code is:
Private Sub PatientFields()
txtFirstName.Text = pa.Tables(0).Rows(intcurrentindex).Item("Forename").ToString()
txtLastName.Text = pa.Tables(0).Rows(intcurrentindex).Item("Surname").ToString()
[Code]....
Once the search is executed I want to be able to click "refresh" and the original table is then shown in the datagridview. If I try adding after the search sub is completed:
table.DefaultView.RowFilter = Nothing
I'm loading a DataGridView from a DataView which collects data from a DataTable. I use the DataView to filter, this is the
Dim dv As New DataView
dv = DataSet4.Tables("TABLA1").DefaultView
dv.RowFilter = "propietario='" + NombrePro + "'"
[code].....
I am wondering if it is possible to filter data from a datatable.Sample datatable
Quote:
Sno CatID Nos
1 XYZ 25
[code].....
How do I calculate the direction an object is facing in degrees, if object A is at x1, y1 and facing object B which is at x2, y2?
View 2 RepliesI have a datagridveiw combo box with a few values in there. I am trying to capture what user clicked. I tried CellValueChanged, CellContentClicked etc. but nothing works.I want to store this value to a variable (important) and then shift the cursor to Column after user has selected value.
View 4 Replies