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OptionsPattern

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OptionsPattern[f]

is a pattern that stands for a sequence of options given to a function, with default values taken from Options[f]. The options can be of the form opt->value or opt:>value, and might be in arbitrarily nested lists.

OptionsPattern[{$opt_1$->$value_1$, ...}]

takes explicit default values from the given list. The list may also contain symbols f, for which Options[f] is taken into account; it may be arbitrarily nested. OptionsPattern[{}] does not use any default values.

The option values can be accessed using OptionValue.

• • f[x_, OptionsPattern[{n->2}]] := x ^ OptionValue[n]

• • f[x]

• • f[x, n->3]

Delayed rules as options:

• • e = f[x, n:>a]

• • a = 5;

• • e

Options might be given in nested lists:

• • f[x, {{{n->4}}}]

See also Options and OptionValue.