MapIndexed

MapIndexed[f, expr]
applies f to the elements of expr, giving the part specification of each element as a second argument to f.

MapIndexed[f, expr, levelspec]
applies f to all parts of expr on levels specified by levelspec.

Details and OptionsDetails and Options

  • MapIndexed uses standard level specifications:
  • nlevels through n
    Infinitylevels through Infinity
    {n}level n only
    {n1,n2}levels through
  • The default value for levelspec in MapIndexed 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, MapIndexed also applies to heads of expressions and their parts.
  • MapIndexed traverses the parts of expr in a depth-first order, with leaves visited before roots. »
  • MapIndexed always effectively constructs a complete new expression and then evaluates it.
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