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Listable

  • Listable is an attribute that can be assigned to a symbol f to indicate that the function f should automatically be threaded over lists that appear as its arguments.
  • Listable functions are effectively applied separately to each element in a list, or to corresponding elements in each list if there is more than one list.
  • Most built-in mathematical functions are Listable.
  • Example: Log is Listable. Log[ a,b,c ].
  • All the arguments which are lists in a Listable function must be of the same length.
  • Arguments that are not lists are copied as many times as there are elements in the lists.
  • Example: Plus is Listable. a, b, c + x.
  • See the Mathematica book: Section 2.5.3.
  • See also: Thread, Map, Sequence.

    Further Examples

    ff didn't get mapped over the list until it was made listable.

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    This restores ff to be what it was originally.

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