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gives the default value for arguments of the function f obtained with a _. pattern object.
Default[f, i]
gives the default value to use when _. appears as the i^(th) argument of f.
Default[f, i, n]
gives the default value for the i^(th) argument out of a total of n arguments.
Default[f, ...]=val
defines default values for arguments of f.
  • _. represents an optional argument to a function, with a default value specified by Default.
  • The necessary values for Default[f] must always be defined before _. is used as an argument of f.
  • Values defined for Default[f] are stored in DefaultValues[f].
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