Apply[f, expr] or f @@ expr replaces the head of expr by f. Apply[f, expr, {1}] or f @@@ expr replaces heads at level 1 of expr by f.Apply[f, expr, levelspec] replaces heads ...

Clock[] represents a clock variable whose value cycles continuously from 0 to 1 once per second when it appears inside a dynamically updated object such as a Dynamic. ...

Count[list, pattern] gives the number of elements in list that match pattern. Count[expr, pattern, levelspec] gives the total number of subexpressions matching pattern that ...

FreeQ[expr, form] yields True if no subexpression in expr matches form, and yields False otherwise. FreeQ[expr, form, levelspec] tests only those parts of expr on levels ...

Replace[expr, rules] applies a rule or list of rules in an attempt to transform the entire expression expr. Replace[expr, rules, levelspec] applies rules to parts of expr ...

StreamPoints is an option to StreamPlot, ListStreamPlot, and related functions that determines how many streamlines to draw.

StringTake["string", n] gives a string containing the first n characters in " string". StringTake["string", -n] gives the last n characters in " string". StringTake["string", ...

Mathematica's unified symbolic architecture makes it incredibly easy to create dialog boxes that range from the straightforward to the highly elaborate and customized. Every ...

Mathematica's core language and computation capabilities can be accessed not only through its rich interactive notebook interface, but also directly through a command-line ...

Built into Mathematica are hundreds of powerful notational forms that can be arbitrarily combined and immediately accessed through their symbolic representations. Many common ...