SolveAlways[eqns, vars] gives the values of parameters that make the equations eqns valid for all values of the variables vars.
Sort
(Built-in Mathematica Symbol) Sort[list] sorts the elements of list into canonical order. Sort[list, p] sorts using the ordering function p.
Speak
(Built-in Mathematica Symbol) Speak[expr] speaks a spoken representation of the expression expr.
StandardDeviation[list] gives the sample standard deviation of the elements in list. StandardDeviation[dist] gives the standard deviation of the symbolic distribution dist.
StandardForm[expr] prints as the standard Mathematica two-dimensional representation of expr.
StepMonitor is an option for iterative numerical computation functions that gives an expression to evaluate whenever a step is taken by the numerical method used.
StringCases["string", patt] gives a list of the substrings in " string" that match the string expression patt. StringCases["string", lhs -> rhs] gives a list of the values of ...
s_1 ~~ s_2 ~~ ... or StringExpression[s_1, s_2, ...] represents a sequence of strings and symbolic string objects s_i.
StringPosition["string", " sub"] gives a list of the starting and ending character positions at which " sub" appears as a substring of " string". StringPosition["string", ...
StringReplace["string", s -> sp] or StringReplace["string", {s_1 -> sp_1, s_2 -> sp_2, ...}] replaces the string expressions s_i by sp_i whenever they appear as substrings of ...