How to | Get Elements of Lists

Lists are very important structures in the Wolfram Language. Lists allow you to treat any kind of collection of objects as a single entity. Sometimes you need to pick out or extract individual elements or groups of elements from a list.

Set up a list of the first 10 squares (stored as v):

Use Part to pick the third element of the list:

Or use [[...]] (the short form notation for Part):

Combine ;; (the short form for Span) with Part to pick out the elements from 1 to 5:

Pick out elements 5 through 8 of the list:

Pick the last 7 elements (negative indices count from the end):

    

A matrix in the Wolfram Language is a list of lists of the same length. You can pick out elements from a matrix just like you would from a list.

Set up a 5×5 matrix of integers:

Use MatrixForm to see it laid out as a matrix:

The first part of the matrix is the first row:

  • Getting Pieces of Lists
  • Adding, Removing, and Modifying List Elements
  • Manipulating Elements of Lists
  • Testing and Searching List Elements
  • Vectors and Matrices
  • How to: Work with Lists
  • Part  MatrixForm

  • Elements of Lists
  • Rearranging & Restructuring Lists
  • Parts of Expressions
  • Parts of Matrices
  • "How to" Topics