Article - LabVIEW 8.5 Feature - For Loop Conditional Terminal

[Jim_Kring]

[cross-post]

Hi All,

I've written an article about a new feature in LabVIEW 8.5 that I think is really useful.

• LabVIEW 8.5 Feature - For Loop Conditional Terminal

As usual, your feedback is most welcome

Thanks,

-Jim

[Ray.R]

Excellent article Jim,

It's one of those features that I am starting to adopt, so it's good to be reminded of it.

Just one comment about the article.  You're missing the word "see" in the text below:

"In the screenshot below, you can the difference between the classic For Loop and one with a Conditional Terminal."

                                              ^see^

Message Edited by JoeLabView on 07-07-2008 11:59 AM

[Jim_Kring]

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@JoeLabView wrote:

Excellent article Jim,

It's one of those features that I am starting to adopt, so it's good to be reminded of it.

Just one comment about the article.  You're missing the word "see" in the text below:

"In the screenshot below, you can the difference between the classic For Loop and one with a Conditional Terminal."

                                              ^see^

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Hi JLV,

Thanks for the feedback and for your attention to detail!  Sometimes my brain gets ahead of my fingers 🙂

Yes, I really love this feature and have finally started to use it regularly.  Now that I am, I can't imagine life without it.

Cheers,

-Jim

[smercurio_fc]

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@Jim Kring wrote:

Yes, I really love this feature and have finally started to use it regularly.  Now that I am, I can't imagine life without it.

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I can. I'm still at 8.2.

[Jim_Kring]

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@smercurio_fc wrote:

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@Jim Kring wrote:

Yes, I really love this feature and have finally started to use it regularly.  Now that I am, I can't imagine life without it.

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I can. I'm still at 8.2.

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I have to switch between 8.5 and 8.2 and whenever I have to use 8.2, I'm disappointed when I can't find this feature 😞

[ShotSimon]

Nice Article...reminds me of the nuggets you see on the forums.
 
I like the file delete example.  I had a flashback to when I first learned batch files in DOS. In the course of minutes I managed to rename every file in my C: drive:)  Luckily I had and image backup but very powerful stuff.
 
A hybrid conditional FOR loops...just another good reason for using auto indexing.
 
Thanks,
 
-SS

[JB]

Thank you Jim for one more interesting article.

My humble suggestion would be to complete the article by adding an example that shows the differences between a for loop with conditional terminal and a while loop (--> no need to extract the array size and to compare it with the loop index to stop after the last element of the array).




Message Edité par JB le 07-08-2008 08:47 AM

[tst]

JB, you should note that this fails to account for the empty array case. To properly simulate the FLwB, you need to wrap the while loop in a case structure and only execute it if the array is not empty.

[Jim_Kring]

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@JB wrote:
Thank you Jim for one more interesting article.

My humble suggestion would be to complete the article by adding an example that shows the differences between a for loop with conditional terminal and a while loop (--> no need to extract the array size and to compare it with the loop index to stop after the last element of the array).




Message Edité par JB le 07-08-2008 08:47 AM

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I'm glad you found the article interesting 🙂

And, thanks for the suggestion -- there is certainly value in seeing the For Loop and While Loop implementations side-by-side, although they are not equivalent when the input array is empty (as using a While Loop to iterate over an ordered set gets complicated/ugly when we try to iterate over empty sets):

First, there is a bug in your upper loop: The decrement operation could cause the While Loop could execute infinitely, since the array length is zero and 0 -1 = -1 which is always less than (i.e., never equal) to i (which starts at 0 and increments on each iteration of the loop).  This is easily fixed by removing the decrement 😉

Second, the While Loop implementation would output a TRUE if the random number passed into the loop were 0, which is the default value of integers (the input array type).

For my article, what I really wanted to highlight is how a For Loop can behave more like a While Loop rather than the inverse.  For example, a For Loop is really a specialized While Loop that is optimized for iterating over ordered sets (iterating a pre-determined number of times is a For Loop's raison d'etre).  The Conditional Terminal allows one to conveniently break, should an exceptional condition occur while iterating over an ordered set.

Cheers,

-Jim

[DavidU]

Hi,
Good Article - I'm just starting to use these.

Just one comment:
The two for loops in Example 2 - searching an array -  will give different outputs if there is more than 1 match in the array. The first will give the index of the last matched element and the second will give the first matched element.

Dave