Access Functions

# S: List -> RngIntElt

The length of the list \(S\).

IsEmpty(S): List -> BoolElt

Return whether \(S\) is empty (has zero length).

S[i]: List, RngIntElt -> Elt

Return the \(i\)-th term of the list \(S\). If either \(i \leq 0\) or \(i > \#S + 1\), then an error results. Here \(i\) is allowed to be a multi-index (see Section Multi-indexing for the interpretation).

S[I]: List, [RngIntElt] -> List

Return the sublist of \(S\) given by the indices in the sequence \(I\). Each index in \(I\) must be in the range \([1..l\)], where \(l\) is the length of \(S\).

IsDefined(L, i): List, RngIntElt -> Elt

Checks whether the \(i\)th item in \(L\) is defined or not, that is it returns true if \(i\) is at most the length of \(L\) and false otherwise.