dcsimg
Login | Register   
LinkedIn
Google+
Twitter
RSS Feed
Download our iPhone app
TODAY'S HEADLINES  |   ARTICLE ARCHIVE  |   FORUMS  |   TIP BANK
Browse DevX
Sign up for e-mail newsletters from DevX

By submitting your information, you agree that devx.com may send you DevX offers via email, phone and text message, as well as email offers about other products and services that DevX believes may be of interest to you. DevX will process your information in accordance with the Quinstreet Privacy Policy.


Tip of the Day
Language: Visual Basic
Expertise: Intermediate
Aug 7, 1997

WEBINAR:

On-Demand

Building the Right Environment to Support AI, Machine Learning and Deep Learning


String Surprise

I was developing a CGI application that read a database and pieced together the fields into a string for representation as an HTML form. The surprise came when I found how slow it was-20 seconds was unacceptable for the task. I first suspected the database access and thought there was no way to improve it; however, upon investigating further, it turned out to be the loop that concatenated the fields into the string. A simple change took the run time of the routine down to about one second. In this simplified example, instead of writing this code:
 
For i = 1 To 10000
        strHTML = strHTML & strField & vbTab
Next i
Break it down into something like this:
 
For i = 1 To 100
        strTemp = ""
        For j = 1 to 100
                strTemp =  strTemp & strField _
                        & vbTab
        Next j
        strHTML =  strHTML & strTemp 
Next i
Admittedly, the number of concatenations is high, but the difference is astounding. In the 16-bit world, the second example is about 20 times faster than the first on my machine. However, in VB 32-bit, my Pentium 133 with 32 MB RAM takes 48 seconds for the first case and less than one second for the second case. I hesitate to suggest a precise speed improvement because of the complexity of Windows 95 and different hardware, but if you must concatenate large numbers of strings, this could become a make-it-or-break-it problem.
Nick Snowdon
 
Comment and Contribute

 

 

 

 

 


(Maximum characters: 1200). You have 1200 characters left.

 

 

Sitemap
Thanks for your registration, follow us on our social networks to keep up-to-date