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Array size-- what is reasonable?

7 posts in this topic

How large an empty array is reasonable?

My program uses two array, one element wide, and 25 to some thousands of elements high. I can do some programming to repeatedly redim the array, or I can initially, say, set it to 10,000 rows, with many of them likely being empty. Seems like sloppy programming to me, making the array larger than it needs to be, but if it saves constant redimming (which seems to take time), perhaps the better approach?

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Start with an array that is at least as large as the largest size you think you'd need, then after you've filled it, redim it once to shrink it to size.


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#3 ·  Posted (edited)

The general solution, when you don't know what the final size of the array is going to be, is to double it in size every time you run out of array space.

Other than than that, I think is mainly a personal taste issue on which size you start with your array definition.

Edited by MvGulik

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I would also recommend if you are looking at using a larger array, is to have the number of elements in the 0 index $Array[1000] = [999, "Index1","Index2.. because I have read somewhere from a Dev that Ubound($Array) becomes a little slower* the more elements you have.

*in terms of the ms or something.


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#7 ·  Posted (edited)

because I have read somewhere from a Dev that Ubound($Array) becomes a little slower* the more elements you have.

Would only really matter if the Ubound() is used inside the loop code. In which case you should drop its result in a variable before entering the loop anyway. A Ubound() that used inside the for-next loop statement itself is only executed one time. (at the moment the for part is initiated.) Edited by MvGulik

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