...: Marsh Chatter
Choices… A Recurring Series: StringBuilder…
String concatenation (e.g. a fancy word for joining strings) is one of the most frequent processes a program performs. Unfortunately, done wrong it can be the major cause of a slow running program – especially when the concatenation is buried in a loop.
Little Background? What is this Immutable thing?
Don’t you just love terminology? Oh so necessary, but the hard part of learning. In short, the common dictionary definition for immutable is something that doesn’t change.
In our industry, strings are known to be immutable; that is, if you change a string, your program actually creates a new one and then deletes the original. There is a cost in time and memory for this process. On top of that – strings are one of the most memory intensive data types we have. Hence, this type of string operation tends to be slow.
Help is in the Framework
Within the .NET Framework is the StringBuilder object which enables fast string handling. Let me repeat that... fast string handling. If you've used it - you know! If you haven't, it is time to learn!
Testing, Examples, and Results on the web
Each of these articles offer great detail, suggestions, and results. There is no reason for you or I to duplicate their testing methods - unless of course you are just looking for a challenge.
Once you see the results in your own code, you might as a general rule, for consistency - argue for using the StringBuilder objects for any string concatenation. Of course, there are always caveats to any "rule"; such as, the slight cost in memory or processor cycles in setting up the object prior to usage.
If you're tacking 2 or 3 strings together, you probably aren't going to save much time, however, if your code will concatenate more or a variable number of strings together, you will probably want to use a StringBuilder to perform that work. This is especially true if the concat will occur within a loop.
Future - Choices… A Recurring Series:
While string concatenation is slow, your code probably has bigger optimization targets. One of the most common is accessing data in files (e.g. hard drive speed issue), or accessing data in files across a network (e.g. significant bandwidth issues).
We will look at potential solutions when using data files (e.g. file-based databases) in your programs. Specifically, this series will relate to web applications. See you then.