Map

Map[f,expr] or
applies f to each element on the first level in expr.

Map[f,expr,levelspec]
applies f to parts of expr specified by levelspec.

Map[f]
represents an operator form of Map that can be applied to an expression.

Details and OptionsDetails and Options

  • Map uses standard level specifications:
  • nlevels through n
    Infinitylevels through Infinity
    {n}level n only
    {n1,n2}levels through
  • The default value for levelspec in Map is .
  • A positive level n consists of all parts of expr specified by n indices.
  • A negative level -n consists of all parts of expr with depth n.
  • Level consists of numbers, symbols, and other objects that do not have subparts.
  • Level corresponds to the whole expression.
  • With the option setting Heads->True, Map includes heads of expressions and their parts.
  • Map always effectively constructs a complete new expression and then evaluates it.
  • If expr is an Association object, Map[f,expr] applies f to the values in the association.
  • If expr is a SparseArray object, Map[f,expr] applies f to the values or subarrays that appear in expr.
  • Map[f][expr] is equivalent to Map[f,expr].

ExamplesExamplesopen allclose all

Basic Examples  (8)Basic Examples  (8)

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Alternative input form:

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Use explicit pure functions:

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Map at top level:

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Map at level :

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Map at levels and :

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Use a map operator:

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Map a function over values in Association:

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Map at the second level of a nested Association:

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Map at several levels in an Association:

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Introduced in 1988
(1.0)
| Updated in 2014
(10.0)