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Programming puzzles: processing lists!
04-28-2017, 08:53 PM
Post: #57
RE: Programming puzzles: processing lists!
(04-28-2017 03:40 PM)pier4r Wrote:  I have problems with this one [#6]... At the end one has \GSLIST that seems not to work when the list to sum is {1. } (I have approximate mode on, and at first I run tests with 10 elements, not 100, to see if I did everything correctly)

Could you confirm?

I can definitely confirm -- you have provided perfectly legitimate input to the program and the approach I used simply doesn't work for that case. It actually falls apart in two separate ways, and I should have remembered both situations as I have hit upon both of them before. Specifically:

1) DOSUBS normally provides a list as its result, EXCEPT for when that list would be empty. In that situation, it doesn't return anything at all. While I disagree with how it works (I think it should return an empty list instead), this isn't the first time I've hit on this issue and I should have remembered it. Ouch. I need to take another look at how I do that first step to address it. It may also be an issue for some of my other submissions.

2) Yes, ΣLIST needs a list of at least 2 elements. I've run into this one before as well. Like I said, I need more practice with list processing on this platform! I think you've hit on the easiest patch for this (adding a 0).

(04-28-2017 03:40 PM)pier4r Wrote:  You #3 is very fast!

It is, because SUB on a list is very efficient. It really doesn't have to do much. The other challenges that I used SUB for will probably be very fast as well. If I didn't make some other silly mistake! Smile

(04-28-2017 03:40 PM)pier4r Wrote:  Side question.
[lots of code...]

Haven't spent a lot of time looking at this just yet, but my suspicion is that the issue has to do with which variables are already defined and which aren't when the code is parsed.

In your supplied code, you are referencing listSize in the program provided to the local var before the var has actually been created (it is created when the → step is executed). At that point, it is simply assumed to be a var name instead of the var itself (since it hasn't actually been created yet). That's probably why it shows up as 'listSize' instead of listSize when the code is run -- it wasn't a known variable when the code was compiled.
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RE: Programming puzzles: processing lists! - DavidM - 04-28-2017 08:53 PM



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