At 09:14 AM 2/15/02 -0500, Robert Rycroft wrote:
>Is there any way to use Lingo to work with a n x m matrix? For example,
>let's say I have data that could be stored in a matrix with 100 rows and 2
>columns. I seem to recall reading about it somewhere. Something about
>putting linear lists inside linear lists, but cannot find the source and
>cannot figure out how to access the specific elements of the matrix. For
>example, how would I access the element in row 62, column 2?
>
>I am trying to use Lingo to write a simulation that was originally written
>in BASIC. In BASIC multi-dimensional matrices are easy to work with.
>
>Thanks.
>
>Robert Rycroft
>[EMAIL PROTECTED]
Here is a generic array example. As a good exercise, convert it to an object!
Note that you don't call the 'array' handler directly. Instead, use the
defineArray, setArray, and getArray functions. I just made an 'array'
function so I didn't have to duplicate the boundary checks. The other
functions follow the 'array' function.
-- Array example
-- Tab Julius ([EMAIL PROTECTED])
-- 2/15/2002
on array func, whichArray, x, y, newValue
if (not listP(whichArray)) then
-- Uh oh, not a list!
return(#Error)
end if
if (not y or y > count(whichArray)) then
-- Y out of bounds! Too low or too high
return(#Error)
end if
subArray =getAt(whichArray, y)
if (not x or x > count(subArray)) then
-- X out of bounds! Too low or two high
return(#Error)
end if
thisElement =getAt(subArray, x) -- Get the current one regardless
if (func = #Set) then
setAt(subArray, x, newValue)
end if
return(thisElement)
end
on defineArray maxX, maxY
-- Build an array x by y. Call this first, before getArray or getArray
newArray =[] -- This is the master list
repeat with y =1 to maxY -- Go through each "row"
newSubArray =[] -- Define a sublist
setAt(newSubArray, maxX, 0) -- And create the maximum entry
add(newArray, newSubArray) -- And add it to the master list
end repeat
return(newArray) -- Return back to caller
end
on setArray whichArray, x, y, newValue
-- Call this function to set a value in your array
-- It returns the previous value that was there, or #Error
result =array(#Set, whichArray, x, y, newValue)
return(result)
end
on getArray whichArray, x, y
-- Call this function to get a value from your array
result =array(#Get, whichArray, x, y)
return(result)
end
Use it like this:
myArray =defineArray(5, 5)
put myArray
-- [[0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0],
[0, 0, 0, 0, 0]]
setArray(myArray, 3, 2, "Test")
setArray(myArray, 5, 5, 99)
put myArray
-- [[0, 0, 0, 0, 0], [0, 0, "Test", 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0,
0], [0, 0, 0, 0, 99]]
put getArray(myArray, 7, 7)
-- #error
put getArray(myArray, 3,1)
-- 0
put getArray(myArray, 3, 2)
-- "Test"
put getArray(myArray, 5, 5)
-- 99
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