f /: lhs = rhs assigns rhs to be the value of lhs, and associates the assignment with the symbol f.

Tally[list] tallies the elements in list, listing all distinct elements together with their multiplicities.Tally[list, test] uses test to determine whether pairs of elements ...

Thread[f[args]] "threads" f over any lists that appear in args. Thread[f[args], h] threads f over any objects with head h that appear in args. Thread[f[args], h, n] threads f ...

PermutationCycles[perm] gives a disjoint cycle representation of permutation perm.

MapIndexed[f, expr] applies f to the elements of expr, giving the part specification of each element as a second argument to f. MapIndexed[f, expr, levelspec] applies f to ...

ConversionRules is an option for Cell that can be set to a list of rules specifying how the contents of the cell are to be converted to external formats.

Except[c] is a pattern object which represents any expression except one that matches c. Except[c, p] represents any expression that matches p but not c.

Intersection[list_1, list_2, ...] gives a sorted list of the elements common to all the list_i.

Patterns stand for classes of expressions. They contain pattern objects that represent sets of possible expressions. Pattern objects. When several pattern objects with the ...

Position[expr, pattern] gives a list of the positions at which objects matching pattern appear in expr. Position[expr, pattern, levelspec] finds only objects that appear on ...