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From: vinson@linc.cis.upenn.edu (Jack Vinson)
Newsgroups: comp.lang.lisp
Subject: another question, arrays
Message-ID: <43929@netnews.upenn.edu>
Date: 30 May 91 14:38:31 GMT
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Me again,  I am also playing with arrays for the first time in lisp and am
wondering what kind of interesting functions there are for messing with them.
In particular I will be frequently updating one array by moving elements down
into the array.  ie if the array is (1.2 1.1 1.2 1.3 1.1 1.0) and new data is
1.2 I want to put the new info at the 'beginning' of the array and shift
everything down, so I would get (1.2 1.2 1.1 1.2 1.3 1.1) with the last element
knocked off.  The way I know how to do this is with a do-loop that copies
element i into i+1, starting from the highest element.

One solution is to just use a gigantic array which I just add new data to the
end of, but this seems like it might waste space ~time~.  Which is more
expensive, keeping track of five 20x2 arrays the above way or creating five
5000x2 arrays and adding data from the beginning?

Jack

Jack Vinson				vinson@linc.cis.upenn.edu