{es}
[es]
es
- an expression sequence
·
A set is an unordered sequence of distinct expressions enclosed in
braces, representing a set in the mathematical sense. The user should not assume
that the expressions will be maintained in any particular order because Maple
uses an ordering convenient for its implementation.
·
A list is an ordered sequence of expressions enclosed in square
brackets. The ordering of the expressions is the ordering of es.
·
Note that es may be empty so that the empty set is represented by
{} and the empty list is represented by [].
·
The elements of a set or list may be extracted via the selection
operation. Thus, if S is a set or list then the ith to jth elements of S can be
obtained by: S[i..j] or equivalently, op(i..j,S). Negative selectors can also be
used. The -1th element is the last, the -2th the second last, and so on.
·
Lists and sets can be nested, in which case selection can be done
in one of two ways: S[i][j]..[n] or S[i,j,..n].
·
Appending an element x to a list L is done by [op(L),x]. Inserting
an element x to a set S is done using the union operator S union {x}.
·
Replacing the i-th element of a list L by x can be done by
subsop(i=x,L). Deleting the i-th element of a list L is subsop(i=NULL,L).
Deleting an element x from a set S is done using the minus operator S minus {x}.
> {x,y,y};
> {y,x,y};
> [x,y,y];
> [y,x,y];
> L
:= [seq(x[i],i=1..4)];
> L[2];
> L
:= [op(L),x[5]];
> L[-3..-2];
> L
:= subsop(2=NULL,L);
> L
:= [1,[2,3],[4,[5,6],7],8,9];
> L[3,2,1];
> L[3][2][1];
type[set], type[list],
selection, op,
nops, union,
intersect, minus,
member, convert,
seq
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