# MaximalBy

MaximalBy[{e1,e2,},f]

returns a list of the ei for which the value of f[ei] is maximal.

MaximalBy[{e1,e2,},f,n]

returns a list of the ei corresponding to the n largest f[ei].

MaximalBy[f]

represents an operator form of MaximalBy that can be applied to an expression.

# Details • Values of f[ei] are compared using the same canonical order as in Sort.
• The maximal ei are returned in the order they appear in the input.
• In the case of MaximalBy[list,f,n], the ei are sorted in the order of decreasing f[ei], with those having the same value of f[ei] being taken in the order they appear in list.
• MaximalBy[list,f, UpTo[n]] gives n elements, or as many as are available.
• MaximalBy[f][expr] is equivalent to MaximalBy[expr,f].
• In MaximalBy[assoc,f,], f is applied to the values of the association assoc.

# Examples

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## Basic Examples(4)

Find the maximal element by its last part:

All maximal elements are returned, in order of appearance:

Obtain the first three maximal elements:

Obtain the first four maximal elements, or as many as are available:

## Scope(1)

MaximalBy works with symbolic expressions, using OrderedQ:

## Properties & Relations(1)

MaximalBy[{e1,e2,},f,n] compares values f[ei] using canonical Order:

TakeLargestBy[{e1,e2,},f,n] compares values f[ei] using NumericalOrder:

## Possible Issues(1)

The maximal element is determined using OrderedQ, not numerical ordering:

Compare numerical values of the elements of the list: