Lambdas: Aggregating Strings

Lambda Expressions: An Introduction

Deborah's Developer MindScape — Sun, 11 Oct 2009 23:57:55 GMT

My presentation at our local Code Camp was fun. I covered a lot of material and had a GREAT audience

re: Lambdas: Aggregating Strings

Deborah Kurata — Mon, 06 Jul 2009 17:46:15 GMT

Hi Jonathan -

Thanks for your suggestion.

It appears that Join is smarter and does not create the excess strings that the Aggregate method creates.

Cool! Thanks again!

re: Lambdas: Aggregating Strings

Deborah Kurata — Mon, 06 Jul 2009 17:39:04 GMT

Hey Shawn -

Thanks for stopping by my blog.

Yes, just because you can do something does not necessarily mean that you should. Have you seen the scuba diving cat? :-)

www.youtube.com/watch

As developers, we always have to evaluate techniques for "fitness of purpose". We have to decide whether a specific technique is appropriate for what our application needs to achieve.

This technique may be fine for an application that will have 1 to 5 email addresses. But it would not work well for a spamming app sending to hundreds of email addresses.

Thanks for your thoughts!

Lamdas

Greg — Mon, 06 Jul 2009 15:24:56 GMT

It's easier to visualy inspect and verify that the for loop exmple works than the lambda based one.

re: Lambdas: Aggregating Strings

Jonathan — Sun, 05 Jul 2009 03:03:45 GMT

I prefer using string.join to accomplish these kinds of things -- the only downside is that it needs a string[]. Luckily, LINQ includes ToArray() to turn the IEnumerable<string> that comes out of Select into a string[].

string email = string.join("; ",custList.Select(c => c.EmailAddress).ToArray());

re: Lambdas: Aggregating Strings

Shawn Wildermuth — Fri, 03 Jul 2009 17:54:22 GMT

The other problem here is that the aggregation of the strings is cool, but the string + string approach involves creation of a lot of strings for the GC to clear. You should be usng a StringBuilder. This is very inefficient on a large number of strings:

string final = "";

for (var x = 0; x < 10; ++x)

{

final += x.ToString();

}

This simple code (like your aggregation) will create about 30 strings that aren't used. Being mindful of the immutability of strings is important.