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What is the most efficient way to do string comparisons that occur very frequently?
The patterns I am checking against are relatively simple, but they must be done quite frequently on a varying types of hardware. Example patterns to match would be similar to:
*Store*
*StoreTest*
*Store###* (### could be any 3 digit pattern
*StoreNightly*
(Anything else that doesn't match the above 4 conditions)
There are several ways that could be used: like operator, compiled regexs, contains method, etc. Is one method generally faster than the others? Can someone guide me to the light as to which would be the most appropriate in this case?
Any suggestions, ideas, or 'constructive criticism' are always welcome.
"There's no such thing as a stupid question, only stupid people." - Mr. Garrison
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How about writing a small application to test your methods?? All you would need is a file full of test data and the StopWatch class. How you write a compare method for each method is up to you.
But, IMHO, given your requirements, my bet would be on compiled Regex. This would give the greatest flexibility, though maybe not the absolute best performance. There are trade-off's you have to consider with other requirements you haven't given.
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I thought the regex.compiled method would be the best way, but I found a couple links online stating that the results could largely vary depending on system hardware.
I debated doing the benchmarks on my box, but I don't want to get caught in the "works fine on my box" scenario w/ this method. If the app was running on one specific machine or server, I would have done the benchmarks already and determined the most appropriate one - just trying to figure out what is the best for wildly different hardware requirements.
I just create a test app with the benchmarks and run it on several diff. machines here and get a baseline avg for each method type.
Dave Kreskowiak wrote: There are trade-off's you have to consider with other requirements you haven't given.
Really, this is just a function that needs to check a given string several different ways and then output another string as output. That simple really, but it will be called a ba-zillion times a day.
Thanks anyways Dave.
Any suggestions, ideas, or 'constructive criticism' are always welcome.
"There's no such thing as a stupid question, only stupid people." - Mr. Garrison
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Just posting the results from my benchmarks in-case anyone else is doing something similar. I had the benchmarks perform with 500,000 iterations with each compare type and then with 2 million each. Benchmarks were performed on numerous machines from a zeon server w/ 16 gig ram to a client box with 512 ram and several in-between.
Fastest to slowest:
1. Regex with RegexOptions.Compiled Or RegexOptions.CultureInvariant Or RegexOptions.IgnoreCase set
2. Contains method
3. LIKE operator
4. Regex with only RegexOptions.Compiled set
#2, 3, 4 would generally end in the order specified above, but not always. #1 always finished as the fastest compare method using regex.ismatch w/ the settings specified.
FYI: I wouldn't use this as the standard for all comparisons done in the future; but rather provided to give you an idea on what options can be used to test against.
#1 seems to be the best performer for this particular routine and the numerous checks being done. Your results may vary as defined by your needs.
Any suggestions, ideas, or 'constructive criticism' are always welcome.
"There's no such thing as a stupid question, only stupid people." - Mr. Garrison
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How to use spell checker in vb.net
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Wouldn't that be covered in the documentation you have on the spell-check component you're using??
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In Visual Studio 2005 .Net, How can you programmatically edit the string value for a Gridview SqlDataSource SelectCommand?
For example, I need to conditionally replace SelectCommand="Select * from [Table1]" with SelectCommand="Select * from [Table2]"
Code snippet Example:
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
<asp:GridView ID="GridView1" runat="server" AllowSorting="True" AutoGenerateColumns="False"
DataSourceID="SqlDataSource1">
<Columns&>
<asp:TemplateField HeaderText="Office Number" SortExpression="O Number">
.... etc..
<asp:BoundField DataField="Status" HeaderText="Status" SortExpression="Status">
<HeaderStyle BackColor="#EBFFEB" />
</asp:BoundField>
.... etc..
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="Data Source=(serverName);Initial Catalog=(databaseName);Integrated Security=True" SelectCommand="Select * from [Table1]"</asp:SqlDataSource>
-
I have tried various AsP <%#variable%> techniques without success.
-
I have also tried the following (in the Page_Load and a Button1_Click sub) :
Dim SqlDatasource1 As New SqlDataSource
Dim GridView1 As New GridView
Dim sSQLDataSource As String
sSQLDataSource = "Select * from [Table2]"
Dim SqlConnectionString As String
SqlConnectionString = "Data Source=(serverName);Initial Catalog=(databaseName);Integrated Security=True"
SqlDatasource1.ConnectionString = SqlConnectionString
SqlDatasource1.SelectCommandType = SqlDataSourceCommandType.Text
SqlDatasource1.SelectCommand = sSQLDataSource
SqlDatasource1.DataBind()
GridView1.DataSource = SqlDatasource1
GridView1.DataBind()
-
Any enlightenment with what I'm missing with the Bound GridView would be greatly appreciated.
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Just in case this can help anybody else, the only solution I was able to find around the Bound GridView SelectCommand was to use a store procedure and pass parameter options via Session variables to return dynamic record sets.
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Hi,
does anybody know if it is possible to export an image from sql 2005 to excel?
Thanks,
T.
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Both Chuck Norris and JSOP know 
Treat them as two separate tasks;
1) fetch an image from SQL Server
2) export data to Excel[^]
I are troll 
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I have set up a typed dataset with 2 tables and a relationship between the 2. For some reason I cannot get the child table to populate.
Here is my code:
Dim ds As New dsEmail
Dim emailHeaderTable As New dsEmail.EmailHeaderDataTable
Dim emailToAdressesTable As New dsEmail.EmailToAddressesDataTable
Dim emailHeaderAdapter As New dsEmailTableAdapters.EmailHeaderTableAdapter
Dim EmailToAddressesTableAdapter As New dsEmailTableAdapters.EmailToAddressesTableAdapter
emailHeaderTable = emailHeaderAdapter.GetData
emailToAdressesTable = EmailToAddressesTableAdapter.GetData
ds.Tables.Add(emailHeaderTable)
ds.Tables.Add(emailToAdressesTable)
For Each emailHeaderRow As dsEmail.EmailHeaderRow In emailHeaderTable.Rows
Dim emailToAddressRow() As dsEmail.EmailToAddressesRow = emailHeaderRow.GetEmailToAddressesRows
For Each toRow As dsEmail.EmailToAddressesRow In emailToAddressRow
MsgBox(toRow.ToAddress)
Next
Next
It appears that the relationship is not there despite it existing in design view of the dataset.
What am I doing wrong?
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Hi,
Im having trouble populating my datagrid control from an ms access database. 1st method I used was through ADODC control and it worked fine. Then I just found a way to lessen the code by creating a class then passing variables through a module. Anyways using the class method my datagrid does not show any data at all. I've removed the datasource control and debugged the program...record count shows that it did get something. Im just in the dark why it won't populate in my datagrid. By the way I'm using vb6 and datagrid through common control 6.0.
populate datagrid
clsPubConnection.GetQuery rs1, "insert query here", 1, 1
Set dgd1.DataSource = rs1
dgd1.Refresh
code inside the class
If rs.State = 1 Then rs.Close
With rs
.CursorType = intCursorType
.LockType = intLockType
.ActiveConnection = cn
.Source = strSqlCommand
.Open
End With
Any help would be greatly appreciated. Thanks in advance 
Aim small, miss small
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Hi friends,
I am just thinking how can i capture the full height of a window that has an scroll bar?
pls give me your sptep by step ideas.
tx
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You would have to find the height of the window and then account for both the visible, and invisible parts of the scrollable area.
The best way to accelerate a Macintosh is at 9.8m/sec² - Marcus Dolengo
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Hai expert cumming.
Thank you for the reply.
"You would have to find the height of the window"
Height of the window using GetWindowRect() is normally returned only the visible area if i am corect?
so how can i retrive the full height of the window?
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Dear All,
Sorry this is a newbie type question though er, I have been programming for er 10 years.
I have found one or 2 C++ pieces of code to enable squiggly lines under a text box. Alas I am no good at C++ anymore and am a VB er person. I find references to an Extended Rich Text control, but I have seen in other applications without rich text control. Unless that is just appearance.
What would be the recommended path for me to try, I can use a rich text box, but ultimately I would like to have a textbox which has a spell check with some other thesauras type feature (it is for a recruitment project and I would like to have words that move people into categories - eg: if it finds FMCG underlines in blue and if the use right clicks it says it is part of Sales, Marketing and Advertising.)
Many thanks
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jinxster wrote: squiggly lines
Not sure what this means.
As far as spell check is concerned, there is some help here[^] and here[^].
In case you are using .Net Framework 3.5, there is a SpellCheck class which might help you.
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He means the lines that show up in say Microsoft Word when you spell something wrong.
The best way to accelerate a Macintosh is at 9.8m/sec² - Marcus Dolengo
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OK. First help link I have posted does that. But not the lines, it changes the font color to red. I dont know if we can change color change to squiggly lines.
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You can with a custom drawing routine, or the link I posted did it with WPF. I've seen it done before, but can't find it now.
The best way to accelerate a Macintosh is at 9.8m/sec² - Marcus Dolengo
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Can some one help
Listbox1 is Data A,B,C,D,E from the SQL base . Id automatically increases every day after entering new values for A,B,C,D,E while Id is date
Every day I want to compare data of the last day with the past 4 day’s data and get values of P1, P2, P3, P4.
Listbox1 =Data from base
Id A B C D E
15 2 4 6 7 8
14 2 6 8 7 2
13 1 4 1 5 8
12 3 3 3 7 2
11 5 6 8 4 1
10 5 8 7 7 7
09 4 4 7 7 7
08 1 2 6 5 4
07 1 5 8 9 5
06 6 6 3 3 2
05 2 2 5 7 8
04 4 7 5 2 3
03 4 6 8 4 9
02 2 2 4 4 7
01 5 7 5 6 1
Listbox2 = Expected results with VB codes
Id P1 P2 P3 P4
15 2 2 1 0
14 0 2 2 0
13 0 0 0 1
12 0 1 1 1
11 1 0 0 1
10 3 0 0 0
09 0 0 0 1
08 1 0 2 0
07 0 0 0 1
06 0 0 1 0
05 1 0 2 1
04 1 0 2 -
03 1 0 - -
02 0 - - -
01 - - - -
The problem is that I want through VB codes to add these values to be added to listbox2
Here P1 at Id 15 = 2 is the value got counting when
Data A at Id 15 = data A at Id = 14 +
Data B at Id 15 = data B at Id = 14 +
Data C at Id 15 = data C at Id = 14 +
Data D at Id 15 = data D at Id = 14 +
Data E at Id 15 = data D at Id = 14 (P1 = 2 Data A & D)
Here P2= 2 is the value got counting when
Data A at Id 15 = data A at Id = 13 +
Data B at Id 15 = data B at Id = 13 +
Data C at Id 15 = data C at Id = 13 +
Data D at Id 15 = data D at Id = 13 +
Data E at Id 15 = data D at Id = 13 (P2 = 2 Data B & E)
Here P3= 1 is the value got counting when
Data A at Id 15 = data A at Id = 12 +
Data B at Id 15 = data B at Id = 12 +
Data C at Id 15 = data C at Id = 12 +
Data D at Id 15 = data D at Id = 12 +
Data E at Id 15 = data D at Id = 12 (P3 = 1 Data D)
Here P4= 0 is the value got counting when
Data A at Id 15 = data A at Id = 11 +
Data B at Id 15 = data B at Id = 11 +
Data C at Id 15 = data C at Id = 11 +
Data D at Id 15 = data D at Id = 11 +
Data E at Id 15 = data D at Id = 11 (P4 =  0 Data)
Etc….etc
Even the user wants to compare up to the past 15 data so that I have up to P15
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What version of visual basic are you using VB6, VB.net or another?
The code will be slightly different in the way you access the listbox depending on the version.
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Thanks for your reply
Iam using MS VB 2008 EXPRESS EDITION
jaakinye
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