Library articles and tutorials

String Concatenation Component

By Michael Balloni, published on 08 Oct 2001
Michael Balloni
Page 5 of 5
  1. Introduction
  2. The solution
  3. The results
  4. Conclusion
  5. Test Code

Test Code

The following is the test code used to generate the performance results displayed earlier in this article. 

Private Sub TestCat()
    Dim test_str As String
    test_str = "foo foo bar"
    TestCatFor 1, test_str
    TestCatFor 5, test_str
    TestCatFor 10, test_str
    TestCatFor 25, test_str
    TestCatFor 50, test_str
    TestCatFor 100, test_str
    TestCatFor 200, test_str
    TestCatFor 500, test_str
    TestCatFor 1000, test_str
    TestCatFor 2000, test_str
    'TestCatFor 5000, test_str
    'TestCatFor 10000, test_str

    test_str = "asd;fjas;dlfu =8-081254j kuva nfajoiruawior "
    TestCatFor 1, test_str
    TestCatFor 5, test_str
    TestCatFor 10, test_str
    TestCatFor 25, test_str
    TestCatFor 50, test_str
    TestCatFor 100, test_str
    TestCatFor 200, test_str
    TestCatFor 500, test_str
    TestCatFor 1000, test_str
    TestCatFor 2000, test_str
    'TestCatFor 5000, test_str
    'TestCatFor 10000, test_str

    test_str = "asd;fjas;dlfu =8-081254j kuva nfajoiruawior " _
        "asd;fjas;dlfu =8-081254j kuva nfajoiruawior asd;fjas;dlfu " _
        "=8-081254j kuva nfajoiruawior asd;fjas;dlfu =8-081254j kuva nfajoiruawior "

    TestCatFor 1, test_str
    TestCatFor 5, test_str
    TestCatFor 10, test_str
    TestCatFor 25, test_str
    TestCatFor 50, test_str
    TestCatFor 100, test_str
    TestCatFor 200, test_str
    TestCatFor 500, test_str
    TestCatFor 1000, test_str
    TestCatFor 2000, test_str
    'TestCatFor 5000, test_str
    'TestCatFor 10000, test_str

    test_str = "asd;fjas;dlfu =8-081254j kuva nfajoiruawior " _
        "asd;fjas;dlfu =8-081254j kuva nfajoiruawior asd;fjas;dlfu " _
        "=8-081254j kuva nfajoiruawior asd;fjas;dlfu =8-081254j kuva nfajoiruawior " _
        "asd;fjas;dlfu =8-081254j kuva nfajoiruawior asd;fjas;dlfu =8-081254j kuva " _
        "nfajoiruawior asd;fjas;dlfu =8-081254j kuva nfajoiruawior asd;fjas;dlfu " _
        "=8-081254j kuva nfajoiruawior asd;fjas;dlfu =8-081254j kuva nfajoiruawior " _
        "asd;fjas;dlfu =8-081254j kuva nfajoiruawior asd;fjas;dlfu =8-081254j kuva nfajoiruawior "

    TestCatFor 1, test_str
    TestCatFor 5, test_str
    TestCatFor 10, test_str
    TestCatFor 25, test_str
    TestCatFor 50, test_str
    TestCatFor 100, test_str
    TestCatFor 200, test_str
    TestCatFor 500, test_str
    TestCatFor 1000, test_str
    TestCatFor 2000, test_str
    'TestCatFor 5000, test_str
    'TestCatFor 10000, test_str
End Sub

Private Sub TestCatFor(ByVal iters As Long, ByVal testStr As String)
    Dim prof As Object
    Set prof = CreateObject("Softwing.Profiler")

    Dim i As Long
    Dim max_i As Long

    max_i = iters

    ' Go traditional.
    prof.ProfileStart
    Dim str As String
    For i = 0 To max_i
        str = str & testStr
    Next

    Dim slow_ms As Double
    slow_ms = prof.ProfileStop

    ' Go cat.
    prof.ProfileStart
    Dim strcat As Catter
    Set strcat = New Catter
    For i = 0 To max_i
        strcat testStr
    Next

    Dim cat_str
    cat_str = strcat.Dump

    ' Clean up the catter.
    Set strcat = Nothing

    ' Stop the clock.
    Dim cat_slow_ms As Double
    cat_slow_ms = prof.ProfileStop

    ' Check that CAT did the same as traditional.
    Debug.Assert cat_str = str

    ' Clean up the profiler.
    Set prof = Nothing

    ' Output results.
    Debug.Print iters & " Run (" & Len(testStr) & "): " & _
        FormatNumber(slow_ms / 10) & " vs. " & FormatNumber(cat_slow_ms / 10)
End Sub
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Related tags

asp, c++

Comments

  1. Dogbite
    06 Jun 2003 at 00:17

    A great idea!  You can also reduce concatenation times by using arrays and the built-in Join() function.  No components required.  Similar performance gain.  Very readable syntax (once you understand the Join arguments).  


    StringVar = JOIN( StringArray(), ElementSeparatorText )


    Redim S(4)
    S(0) = "This is text line 1"
    S(1) = "This is text line 2"
    S(2) = "This is text line 3"
    S(3) = "This is text line 4"
    S(4) = "This is text line 5"


     'assign lines to string variable with comma separator


    vMyString = join(S, ",")


     'dump lines to screen, one element per visual line ("&" executes once)


    response.write join(S, "<br>" & VbCrLf)


     'output array as a table row (elements are separated with "</td><td>")


    response.write "<tr><td>" & join(S, "</td><td>" ) & "</td></tr>"


     'build an option list of codes that exist in a database


    set rs = CreateObject("ADOR.Recordset")
    rs.Open "select [TypeCode] from [CodeTable] order by [TypeCode]", myConnectString, adOpenStatic
    S = rs.getrows '<-- very fast!
    rs.close
    response.write = "<select ...>" & vbcrlf
    response.write = "<option>" & join(S, "</option>" & vbcrlf & "<option>" ) & "</option>" & vbcrlf
    response.write = "</select>" & vbcrlf


     'clear array from memory (if you want to free up memory right away)


    erase S

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