OpenAppend (Built-in Mathematica Symbol)

OpenAppend["file"] opens a file to append output to it, and returns an OutputStream object.

OpenRead (Built-in Mathematica Symbol)

OpenRead["file"] opens a file to read data from, and returns an InputStream object.

OptionsPattern (Built-in Mathematica Symbol)

OptionsPattern[] is a pattern object that represents a collection of options given as rules, where the values of the options can be accessed using OptionValue. ...

OptionValue (Built-in Mathematica Symbol)

OptionValue[name] gives the value of name in options matched by OptionsPattern. OptionValue[f, name] gives the value of name for options associated with the head f. ...

OrderedQ (Built-in Mathematica Symbol)

OrderedQ[h[e_1, e_2, ...]] gives True if the e_i are in canonical order, and False otherwise.

Orderless (Built-in Mathematica Symbol)

Orderless is an attribute that can be assigned to a symbol f to indicate that the elements e_i in expressions of the form f[e_1, e_2, ...] should automatically be sorted into ...

OutputControllableModelQ (Built-in Mathematica Symbol)

OutputControllableModelQ[ss] gives True if the StateSpaceModel object ss is output controllable, and False otherwise.

OutputSizeLimit (Built-in Mathematica Symbol)

OutputSizeLimit is an option for notebooks which specifies the maximum size in bytes of expressions that will automatically be output in their entirety.

OverscriptBox (Built-in Mathematica Symbol)

OverscriptBox[x, y] is the low-level box representation for OverscriptBox[x, y] in notebook expressions.

PageWidth (Built-in Mathematica Symbol)

PageWidth is an option for output streams and for cells which specifies how wide each line of text should be allowed to be.