Append

The collection with value added as its last element.

✓ checked against that system · ! checked, with disagreements (hover a chip)Wolfram LanguageAppend✓↗

Append(collection, value)the collection with value added as its last element.

Append(expr, value)value added as the last operand of any expression, not just a collection.

Typed signatures

Type	Package	Applies
untyped	combinatorics	always
(collection<any>, (missing | value)+) -> collection	compute-engine	always

Domain: Collections

Details

• $Append(c, x) = Join(c, \{x\})$. See Join.
• Appending a list nests it as a single element rather than splicing its contents in — use Join to splice.
• Works on a set as well as a list, and on the operands of any expression.

Examples

Basic #

live ↗

In$\mathrm{Append}(\bigl\lbrack1, 2, 3\bigr\rbrack, 4)$Out$\bigl\lbrack1, 2, 3, 4\bigr\rbrack$

live ↗

In$\mathrm{Append}(\bigl\lbrack a, b, c, d\bigr\rbrack, x)$Out$\bigl\lbrack a, b, c, d, x\bigr\rbrack$

Scope #

A set as well as a list

live ↗

In$\mathrm{Append}(\lbrace1, 2, 3\rbrace, 4)$Out$\lbrace1, 2, 3, 4\rbrace$

Onto the empty list

live ↗

In$\mathrm{Append}(\bigl\lbrack\bigr\rbrack, x)$Out$\bigl\lbrack x\bigr\rbrack$

A lazy Range is materialised first

live ↗

In$\mathrm{Append}(1..3, 4)$Out$\bigl\lbrack1, 2, 3, 4\bigr\rbrack$

Any head, not just a list

live ↗

In$\mathrm{Append}(f(a, b), c)$Out$f(a, b, c)$

Applications #

Adding a row to a matrix

live ↗

In$\mathrm{Append}(\bigl\lbrack\bigl\lbrack1, 2\bigr\rbrack, \bigl\lbrack3, 4\bigr\rbrack\bigr\rbrack, \bigl\lbrack5, 6\bigr\rbrack)$Out$\bigl\lbrack\bigl\lbrack1, 2\bigr\rbrack, \bigl\lbrack3, 4\bigr\rbrack, \bigl\lbrack5, 6\bigr\rbrack\bigr\rbrack$

live ↗

In$\mathrm{NestList}(\operatorname{\_1}↦\mathrm{Symbol}(x), \bigl\lbrack a\bigr\rbrack, 5)$Out$\bigl\lbrack\bigl\lbrack a\bigr\rbrack, \mathrm{Symbol}(x), \mathrm{Symbol}(x), \mathrm{Symbol}(x), \mathrm{Symbol}(x), \mathrm{Symbol}(x)\bigr\rbrack$

Properties #

$Append(c, x) = Join(c, \{x\})$. See Join

live ↗

In$\mathrm{Append}(\bigl\lbrack1, 2, 3\bigr\rbrack, 4)=\mathrm{Join}(\bigl\lbrack1, 2, 3\bigr\rbrack, \bigl\lbrack4\bigr\rbrack)$Out$\mathrm{True}$

Appending adds exactly one element. See Length

live ↗

In$\mathrm{Length}(\mathrm{Append}(\bigl\lbrack1, 2, 3\bigr\rbrack, 4))=\mathrm{Length}(\bigl\lbrack1, 2, 3\bigr\rbrack)+1$Out$\mathrm{True}$

Possible issues #

Appending a list nests it as a single element rather than splicing its contents in

live ↗

In$\mathrm{Append}(\bigl\lbrack1, 2, 3\bigr\rbrack, \bigl\lbrack9\bigr\rbrack)$Out$\bigl\lbrack1, 2, 3, \bigl\lbrack9\bigr\rbrack\bigr\rbrack$

About

Examples	11
Checked against	Wolfram Language 11 agreemathlib4 6 agree1 error
Crosswalk	Wolfram Language

Implementation

mappedmathlib4packages/oracle/src/mappings.ts

The value as a new last element; a list value onto a list of scalars fails to elaborate (ours nests it as one element), as does a set.

See also: Join, Prepend