TextData[exprs] is a low-level representation of the contents of a textual cell.

WordSeparators is an option for Read, Find, and related functions that specifies the list of strings to be taken as delimiters for words.

$FrontEndSession is a global symbol that represents the current session of the front end from which the kernel is being run.

$Messages gives the list of files and pipes to which message output is sent.

Cases[{e_1, e_2, ...}, pattern] gives a list of the e_i that match the pattern. Cases[{e_1, ...}, pattern -> rhs] gives a list of the values of rhs corresponding to the e_i ...

For many applications, high-level constructs like Manipulate and TabView will immediately give you the dynamic interactivity you need. Mathematica also allows you to create ...

In addition to a rich set of standard file operations, Mathematica's unified symbolic architecture makes it easy to apply algorithmic approaches and efficient higher-level ...

In an expression like f[{a,b,c}] you are giving a list as the argument to a function. Often you need instead to apply a function directly to the elements of a list, rather ...

ButtonBox[boxes] is a low-level box construct that represents a button in a notebook expression.

InterpretationBox[boxes, expr] is a low-level box construct that displays as boxes but is interpreted on input as expr.