Data Type question / Sort

M

Marston

Hi

I'm trying to prep some values for a multi-column sort in an array.
The array contains something like 300,000 by 10 values
I've seen quick sort routines that can sort on a single value, but not
perform sorts within the initial sort.

My idea was to concatenate all my values into a single value and then
sort on it. The problem I'm facing is that my numbers would have to be
on the order of ~10E+18-1 long

The way the routine works is it looks at the numbers in each column
whose length is fixed and never has a situation where there are
leading zeros to cause problems.

Col 1 Col 2 Col 3 Col 4 Col 5 Col 6
Row x: aaa bbb cc ddddd e fff

I only need to arrange based on these 6 columns not the entire 10 in
the array

My problem is when I create a number like aaabbbccdddddefff it appears
to have
problems with the "efff" portion. I checked each individual component
(which I'm multiplying by some 1nnnn where n is some number of zeros -
and they all work fine, its just once I tried to add things. Its like
it drops values off.
I have the variables defined as Double which I thought would work.

Any thoughts?
 
T

Tom Ogilvy

A long can store numbers in this range: 2,147,483,648 to 2,147,483,647

A double can store numbers in this range: -1.79769313486231E308
to -4.94065645841247E-324 for negative values and from 4.94065645841247E-324
to 1.79769313486232E308 for positive values. But only approximately 15
significant digits.
 
M

Marston

I'm trying a similar but slightly different approach now.
Rather than try and turn my values from text to numbers (something
caused by our ERP query tool)
I'm concatenating the values with &s in the order that I want things
sorted and dumping
that to a new column in the array then sorting on it.

Unfortunately, I think the size of the values being sorted must matter
because when I used the quick sort tool that from John Walkenbachs
book (similar to the one I got from Alan Bedan) it sorted an array of
over
300,000 variables in a little over 10 seconds. But with the array I'm
trying to
sort, the strings are very long and I suspect that is slowing the sort
down.
I left it running at work with a timer on it and will see how long it
takes
to run, hopefully not some ridiculous amount.

On the good side though - it does provide a way for sorting across
multiple columns.

One thought though - my original array was 350,000 x 10 - but the
sorting
value uses 6 of the 10 values. Would it be faster to drop those 6
(plus the new one)
to end up sorting on a single column within a 350,000 x 5 array?
 
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