Apply

Apply[f,expr]
or replaces the head of expr by f.

Apply[f,expr,{1}]
or replaces heads at level of expr by f.

Apply[f,expr,levelspec]
replaces heads in parts of expr specified by levelspec.

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

Details and OptionsDetails and Options

  • Apply uses standard level specifications:
  • nlevels through n
    Infinitylevels through Infinity
    {n}level n only
    {n1,n2}levels through
  • The default value for levelspec in Apply is .
  • is equivalent to Apply[f,expr,{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 consists of numbers, symbols, and other objects that do not have subparts.
  • Level corresponds to the whole expression.
  • Apply always effectively constructs a complete new expression and then evaluates it.
  • Apply operates on SparseArray objects just as it would on the corresponding ordinary lists.
  • Apply operates on values only in Association objects.
  • Apply[f][expr] is equivalent to Apply[f,expr].
Introduced in 1988
(1.0)
| Updated in 2014
(10.0)