Parts of Expressions

The Wolfram Language's unified symbolic architecture allows immediate generalization of part-oriented list operations to arbitrary expressionssupporting operations both on individual parts, and on collections of parts at specified levels in expression trees.

ReferenceReference

Part (..[[..]]) get any part of an expression (reset with =)

Length  ▪  First  ▪  Last  ▪  Most  ▪  Rest  ▪  Take  ▪  Drop  ▪  Extract

ReplacePart replace numbered parts of an expression

Append  ▪  Prepend  ▪  Insert  ▪  Delete  ▪  DeleteCases

Position find the positions of any pattern in an expression

Cases find cases of any pattern in an expression

MapAt apply a function at particular positions in an expression

Map (/@) apply a function at specified levels in an expression

MapAll (//@) apply a function to all parts of an expression

Heads option for specifying whether to include heads

Sow, Reap collect parts "sown" inside of an expression