Documentation

Mathematica Teacher's Edition

Built-in Functions

Lists and Matrices

List Operations

ReplacePart

ReplacePart[expr, new, n] yields an expression in which the n part of expr is replaced by new.
ReplacePart[expr, new, i, j, ... ] replaces the part at position i, j, ... .
ReplacePart[expr, new, , , ... , , , ... , ... ] replaces parts at several positions by new.
ReplacePart[expr, new, pos, npos] replaces parts at positions pos in expr by parts at positions npos in new.

Example: ReplacePart[a, b, c, d, x, 3].
The list of positions used by ReplacePart is in the same form as is returned by the function Position.
If pos and npos both specify multiple parts, each part in pos is replaced by the corresponding part in npos.
See The Mathematica Book on the web: Section 1.8.6 and Section 2.1.4.
See also: Part, Extract, Insert, Delete.

Further Examples