WolframLang: List

By Xah Lee. Date: . Last updated: .

List is the most fundamental data structure of WolframLang.

List[expr1, expr2 etc]
(short syntax: {expr1, expr2 etc})

return a list.

List

(* a list *)
{3, 4, 5}

(* FullForm syntax *)
List[ 3, 4, 5 ]

List can nest in any way.

{3, 4, {1,2}, 5}

Length

Length[expr]
return the length of expression. Length
Length[ {3, 4, 5} ] === 3

List Represents Array/Vector, Matrix, Tree

Vector is List

A vector (linear algebra) is reprented by a list. e.g. {a,b,c} is a 3-dimensional vector.

Matrix is List

A matrix (linear algebra) is reprented by nested list. e.g. a 2 by 3 matrix:

{ {a,b,c}, {1,2,3} }

where

Tree Data Structure is List

A tree data structure is a nested list. e.g. { { {a, b }, m }, {1, 2 } }

TreeForm[ { {{a,b},m}, {1,2} } ]
WolframLang TreeForm 2022-07-06 hdYYw
WolframLang TreeForm 2022-07-06

List