BUILT-IN WOLFRAM LANGUAGE SYMBOL
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.
- 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 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].
Alternative input form:
Use explicit pure functions:
Map at top level:
Map at level 2:
Map at levels 1 and 2:
Use a map operator:
Map a function over values in Association:
Map at the second level of a nested Association:
Map at several levels in an Association:
Introduced in 1988
(1.0)
| Updated in 2014
(10.0)
