On 4/15/2012 6:59 PM, Ian Kelly wrote:
On Sun, Apr 15, 2012 at 4:49 PM, Terry Reedy<tjre...@udel.edu> wrote:
On 4/15/2012 12:16 PM, Ian Kelly wrote:
On Sat, Apr 14, 2012 at 8:57 PM, Shmuel Metz
<spamt...@library.lspace.org.invalid> wrote:
In<87aa2iz3l1....@kuiper.lan.informatimago.com>, on 04/11/2012
at 05:32 PM, "Pascal J. Bourguignon"<p...@informatimago.com> said:
You're confused. C doesn't have arrays. Lisp has arrays. C only has
vectors
According to the authors of C, the C standard committee, and probably
hundreds of C authors, C has 'arrays', not 'vectors'. Fortran also has
'arrays', with some systems having hardware or software extensions for
vector (and matrix) processing (where vectors have the operations I
specify below and matrixes have *their* operations).
(See for instance https://en.wikipedia.org/wiki/Fortran )
Neither C nor any other programming language has vectors ;-)
Generally not as a built-in type, though vector functions that treat 1-d
arrays as vectors are common. So are added matrix classes and functions.
AFAIK, C++ nomenclature notwithstanding, a vector is just an array
with only one or indices, so all languages that have arrays have
vectors.
Confusing representation with concept is not very helpful. In biology, a
vector is something that carries something from here to there. That is
related to the astronomical/geometric/mathematical meaning.
Vectors are magnitude with direction, often represented by 1-d array of
projections on coordinate axes. If a = 1,2,3 and b = 3,2,1 are
(mathematical) vectors, then a+b = 4,4,4; 2*a = 2,4,6; and a*b = (3+4+3) =
10.
I'm referring to the programming usage, not the mathematical usage.
See definition #4 at dictionary.com, or definition #8 at wiktionary.
But you will not find that meaning in
http://www.merriam-webster.com/dictionary/vector
The mathematical usage *is* the programming usage in many programming
languages and communities -- including Python. CPython lists are
implemented as C arrays.
===
Terry Jan Reedy
--
http://mail.python.org/mailman/listinfo/python-list
