Map

Map[f,expr] or f/@expr

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 Options

• Map uses standard level specifications:
•  n levels 1 through n Infinity levels 1 through Infinity {n} level n only {n1,n2} levels n1 through n2
• The default value for levelspec in Map is {1}.
• 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 1 consists of numbers, symbols, and other objects that do not have subparts.
• Level 0 corresponds to the whole expression.
• With the option setting , 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].

Examples

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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 2:

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Map at levels 1 and 2:

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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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