get the last index of a string array

[sinclair15]

how to get the last index of a string array? the array size is always changes in certain situations

[GerdW]

Hi sinclair,

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@sinclair15 wrote:

how to get the last index of a string array? the array size is always changes in certain situations

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You want to know the ArraySize? Then why don't you determine the ArraySize?

(When you want to get the value of the last array element (of a 1D array) then use DeleteFromArray…)

[sinclair15]

Ok gerd thankyou, the problem has been resolved

[GerdW]

Hi sinclair,

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@sinclair15 wrote:

the problem has been resolved

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In which way did you solve the problem?

(You know in a public forum it's important to provide solutions to questions with some explanations. Others may benefit from your detailed answer - the same as you learned from asking…)

[altenbach]

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@sinclair15 wrote:

how to get the last index of a string array? the array size is always changes in certain situations

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For any array (not just an array of strings, what I assume you mean by "string array"), the index of the last element (I assume that's what you mean by "last index") is the array size minus one.

[paul_a_cardinale]

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@GerdW wrote:

Hi sinclair,

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@sinclair15 wrote:

how to get the last index of a string array? the array size is always changes in certain situations

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You want to know the ArraySize? Then why don't you determine the ArraySize?

(When you want to get the value of the last array element (of a 1D array) then use DeleteFromArray…)

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Note that when you don't wire the "index" input of "Delete from Array", it deletes the last element.

[altenbach]

Obviously I am not versed in reading between the lines, but from the question, I assume ....

• They are just interested in the index, not the value of the element (Delete from array does not give that information)
• They want to keep the array intact. (Delete from array does not do that, so we need to branch the array first and continue with the intact version).

Of course the deeper question is why the array size is constantly changing and why they are interested in the "last index" (sic). Maybe they just want to determine the location where to append new data (e.g. using the misguided "insert into array"), something that is not necessary with the right primitive (i.e. "built array", possibly in concatenate mode). 😄

Sometimes the code can be rewritten to keep the array size constant and be less taxing on the memory manager, but for that we would need more detail about the requirements....

[GerdW]

Hi,

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@altenbach wrote:

• They want to keep the array intact. (Delete from array does not do that, so we need to branch the array first and continue with the intact version).

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I never mentioned to use the array output of DeleteFromArray, I just suggested to use the "deleted element" output of that node.

For the broader audience: DeleteFromArray can be used as a shortcut to "index the last element of an 1D array".

(I know that you know this, Christian. 🙂 )

[altenbach]

I sure hope that "delete from array" can eliminate the creation of the shortened array output if nothing is connected to it. I have never done any benchmarking.

(Back in the nineties, "delete from array" did not even exist and I still rarely use it) 😄

[daveTW]

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@altenbach wrote:

...

(Back in the nineties, "delete from array" did not even exist and I still rarely use it) 😄

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You are right, and I made myself a polymorphic VI with that function. I called it "Pop Array Element" since I had some Perl- experience and there this task was named this way 😁

It also took me some time to get used to the "Delete Array Element"... 

Was Hänschen nicht lernt, lernt Hans nimmermehr! 😉