A DateTime question (Average time)

[stateofidleness]

Hey guys,
I run a "scan" through the rows of a DataGridView and at the end of the scan, I have stored how long the scan took.

What I want to do is be able to get the average scan time of all completed scans, but I'm not sure how to do math operations with the Time. (format I have is 00:00:00)

let's say I do 1000 scans, does that mean I have to store all 1000 scan durations to be able to get a current average? any easier way to keep a running average of duration of completed scans?


another thing, How can I test if the Date is Friday?

[stanav]

The duration of each scan is a TimeSpan, not a DateTime value. You can perform an average by keeping track of how many items completed and for each completed item you add the duration to the overall timespan. Get the totalseconds (or miliseconds or minutes... it's up to you to decide how accurate you want to get) from the overall timespan, divide it by the completed count and you have the average scan time of each item.

[JacquesLebrun]

Use the DateTime and TimeSpan variables:

        Dim start As DateTime
        Dim elapsed As TimeSpan
        start = Now
        Delay(1.23)
        elapsed = Now - start
        Debug.Print("Process started at " & start.ToString("HH:mm:ss") & " on " & start.DayOfWeek.ToString)
        Debug.Print("Process took " & elapsed.TotalSeconds & " seconds")

[stateofidleness]

Thought I should add the code I'm using to do a scan time. It uses a StopWatch object.

'In a Timer's tick event for 1000milli
scanTime.Text = _
            mSwatch.Elapsed.Hours.ToString("00") & ":" & _
            mSwatch.Elapsed.Minutes.ToString("00") & ":" & _
            mSwatch.Elapsed.Seconds.ToString("00")

now looking at your code there Jacques, that looks pretty nifty.

let's say I implement your code above to replace mine to keep track of scan durations. to get an average, I would just add the previos elapsed time to 'elapsed' then divide by number of scans completed?

[stanav]

Do something like this:

Dim totalDuration As New TimeSpan(0)
        Dim startTime As DateTime
        Dim completedCount As Integer = 0
        For Each row As DataGridViewRow In DataGridView1.Rows
            startTime = Date.Now
            'Do you scan here with this row
            '
            '
            'When done, add 1 to completedCount
            completedCount += 1
            'Add the elapsed time to totalDuration
            totalDuration += Date.Now.Subtract(startTime)
            'Calculate the average
            LabelAverage.Text = String.Format("Average scan time per item is: {0} seconds", (totalDuration.TotalSeconds / completedCount).ToString("F3"))
        Next

[stateofidleness]

thanks stan, but mine stores the duration of all rows, which is roughly 17 minutes for a full scan to complete. I don't really worry about each row individually.

[JacquesLebrun]

Here is a way to get your average:

        Dim start As DateTime
        Dim elapsed As TimeSpan
        Dim loops As Integer = 3

        start = Now
        For Attempts As Integer = 1 To loops
            Delay(1.23)
        Next
        elapsed = Now - start

        Debug.Print("Process started at " & start.ToString("HH:mm:ss") & " on " & start.DayOfWeek.ToString)
        Debug.Print("Process took " & elapsed.TotalSeconds & " seconds")
        Debug.Print("Average is " & (elapsed.TotalSeconds / loops) & " seconds")

[stanav]

In your original post, you saked:

Hey guys,

let's say I do 1000 scans, does that mean I have to store all 1000 scan durations to be able to get a current average? any easier way to keep a running average of duration of completed scans?

And my code showed you how to do just that. It calculates and updates the average every time a item scan completes and you don't have to wait 17 minutes to get the average.

[stateofidleness]

but i'm not really doing an "item" scan, i'm doing a "list" scan. after it goes through all the rows (17 minutes later), it increments my "scanCount" variable by 1.

Jacques' last post looks like it should work, I just need to convert the seconds to minutes with a simple "/60".

[JacquesLebrun]

Debug.Print("Average is " & (elapsed.TotalMinutes / loops) & " minutes")

[stanav]

When I use the term "item", it means whatever object that your scan performs on. And in you original post again, you said:

I run a "scan" through the rows of a DataGridView and at the end of the scan, I have stored how long the scan took.

So in the code I posted, I used a for each loop to loop thru a datagridview.rows collection, which is exactly what you wanted in the beginning. But anyway, it's your program and you can choose to change it anytime when need to, right

[stateofidleness]

I hear ya, translation error. 'ppreciate the help from you both!