Dear GAP Forum,
On 11 Jun 2007, at 14:45, muniru asiru wrote:
I need help.
While working with Gap, I came accross the following
list of list of list with 10,3 and 7 items
respectively. My interest is to REPLACE (please note)
this list of list of list (a5, below) with a list of
list so that I will have 30 elements made up of 7
elements in each list of list.
Thank you
There is a more general solution using my function "Array" (attached). That
means, thereby you can reformat deliberately your list structure:
a5:=[ [ [ ... ] ] ];
a307:=Array([30,7]);
a210:=Flat(a5);
k:=0;
for i in [1..30] do
for j in [1..7] do
k:=k+1;
a307[i][j]:=a210[k];
od; #j
od; #i
gap> Length(a307);
30
gap> Length(a307[1]);
7
gap> a210test:=Flat(a307);;
gap> a210=a210test;
true
gap>
all the best, Rudolf Zlabinger
Array:=function(bounds)
# creates an array of empty lists of arbitrary nesting levels (dimensions)
# and bounds for each level
# bounds is a list of positive integers determining the length of each dimension
# the length of bounds is the dimension of the array
# at element level the dimension of the array is 1 higher,
# as the last level are also empty lists
local array,IterateArray;
IterateArray:=function(array,bounds)
# iterative call for decreasing levels of array and bounds
local i,dim,boundsrecall;
# i.. index,
# dim the recent level of bounds,
# boundsrecall.. shortened bounds for recalls
dim:=Length(bounds); # the varying length of bounds
for i in [1..bounds[1]] do # 1 recallcascade for one add
Add(array,[]); # enlarging the recent level of array
if dim>1 then # dim=1 is the last level
boundsrecall:=bounds{[2..dim]}; # shorten bounds for next level
IterateArray(array[i],boundsrecall); # recursion for the next lower level of array
fi; # end of dimension > 1 clause
od; # end of bound loop
return array;
end;
array:=[];
array:=IterateArray(array,bounds); # starting call of add cascade
return array;
end;
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