Difference between function definitions

Question

Possible Duplicate:
Functions vs. patterns

I thought about describing the context in which I faced this problem, but I figured it is general enough and clear enough to pose it as it is.

What is the difference between the two following definitions:
f[x_]:=Sin[x]
g=Sin[#]&
Under what circumstances will the two behave differently? Is any of them preferable as a general practice?

@YvesKlett At the time that one was asked, we had a lot of energy since we were only out there for a week :) — Leonid Shifrin, Dec 04 '12 at 11:31
@LeonidShifrin question on best practice: since my answer is now quite redundant and I am voting to close, should I delete the answer? — Yves Klett, Dec 04 '12 at 11:36
@YvesKlett Since the question is likely going to be closed,I think that does not matter much. — Leonid Shifrin, Dec 04 '12 at 11:37
For some reason, I didn't find the duplicate when I searched for an answer. Thanks! — yohbs, Dec 04 '12 at 11:45
@yohbs What is funny is that I knew precisely the name of the question (functions vs patterns), but when I typed that in SE search, I got nothing. So, I had to look for my past answers to locate it, since I recalled contributing an answer there. SE search quite often sucks. — Leonid Shifrin, Dec 04 '12 at 11:48
I also searched superficially and did not find the answer... — Yves Klett, Dec 04 '12 at 12:00
@LeonidShifrin True that. Googling with site:mathematica.stackexchange.com added to the search terms is often better. — Sjoerd C. de Vries, Dec 04 '12 at 12:52

score 1 · Answer 1 · answered Dec 04 '12 at 11:28

1

Very short answer on one relevant difference (probably much better ones will appear):

A pure function like g will be faster performance-wise, because it gets rid of all the overhead (e.g. pattern matching) involved in the definition of f.

answered Dec 04 '12 at 11:28

Yves Klett

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Difference between function definitions

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