Remove curly brackets _completely_ to map a function to the elements of a list

Question

Most list manipulations can be done with Flatten, Partition and Take. I didn't managed to use them for my need: I'd like to know if there is nice solution to map a function of several variables to a list, and other variables. For examples, given:

f[a_,b_,c_]=a+b+c;

and

list={2,3};

I'd like to calculate f[a,2,3]

Of course, I could use

f[a,list[[1]],list[[2]]]

but I'm looking for something a bit more general, such as

f[a,MysteriousFunction[list]]
(* wished output: a+1+2 *)

Does such a MysteriousFunction exist?

score 1 · Accepted Answer · answered Aug 12 '14 at 17:32

1

f[a_, b_, c_] = a + b + c;
list = {2, 3};
f[a, Sequence @@ list]
(* 5 + a *)

answered Aug 12 '14 at 17:32

Dr. belisarius

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(thanks!) To go slightly further: I'd like to replace something in list before; f[a, Sequence@@list/. 2->4] doesn't work, but f[a, Sequence@@Sequence@@list/. 2->4] does. There's probably a simpler way but I didn't find it yet. – anderstood Aug 12 '14 at 18:08
minor question: is there a reason to use Sequence@@... rather than Sequence[...]? – anderstood Aug 12 '14 at 18:09
@anderstood Nope. Just old vices – Dr. belisarius Aug 12 '14 at 18:10
1

@anderstood f[a, Sequence @@ (list /. 2 -> 4)] – Dr. belisarius Aug 12 '14 at 18:13
Wow. I had tried with curly brackets... I did not know parenthesis were useful elsewhere than in infix notations in Mathematica. – anderstood Aug 12 '14 at 18:16
1

@anderstood You need @@ to replace the head List by Sequence ... Sequence[{1, 2}] != Sequence @@ {1, 2} – Dr. belisarius Aug 12 '14 at 18:30

Remove curly brackets _completely_ to map a function to the elements of a list

1 Answers1