Re: priorities between @, @@ and //
- To: mathgroup at smc.vnet.net
- Subject: [mg108748] Re: priorities between @, @@ and //
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Tue, 30 Mar 2010 05:00:49 -0500 (EST)
To find out, evaluate the expressions.
f@x // g
g[f[x]]
f @@ {a, b}[[2]]
b
For the precedence of operators see :
http://reference.wolfram.com/mathematica/tutorial/OperatorInputForms.html
@ has higher precedence than //
[[ ]] has higher precedence than @@
However, this makes no difference for the last example above
(f @@ {a, b})[[2]] == f @@ ({a, b}[[2]])
True
And if you want to make sure, use parentheses to force the evaluation order.
Bob Hanlon
---- guerom00 <guerom00 at gmail.com> wrote:
=============
Hello all,
Just a quick question : what are the priority between all those
operators ? I mean :
- what is f@x//g ? Is it f[g[x]] or g[f[x]]
- what is f@@{a,b}[[2]] ? Is it f[b] or (f[a,b])[[2]]
You see what I mean... What are the rules for the priority of all
those operators ?
TIA :)