First¶

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description¶

First[expr] gives the first element of expr.

Examples¶

No verified examples yet for this function.

Implementation notes¶

builtin_first (in src/part.c) takes a single argument and returns a deep copy of its first element (args[0]). It returns NULL (unevaluated) when the argument is atomic or has no elements.

Attributes: none registered.

Implementation status¶

Stable — documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

References¶

Source: src/part.c
Specification: docs/spec/builtins/structural-manipulation.md

Notes & additional examples¶

Worked examples¶

In[1]:= First[{a,b,c}]
Out[1]= a

Notes¶

First[expr] returns the first element (part 1) of any expression, not only lists.