MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: multiple outputs from a function


Ben,

just put the output in a list.
Here's an example which gives the first three powers of a variale x

Definition

In[9]:=
pow[x_] := {x, x^2, x^3}

Execution

In[10]:=
y = pow[8]

Result

Out[10]=
{8, 64, 512}

The specific components of the list can then be extracted one by one 
using Part, or [[]]. Example: the second value is

In[13]:=
y[[2]]

Out[13]=
64

Hope this helps,
Wolfgang

Ben Barrowes wrote:

> I feel I must be missing something fundamental...
> 
> How do you write a function (or ?) in Mathematica which produces more 
> than one output?
> 
> Let's say I have some data and I want a single function to calculate the 
> mean, variance, std, etc, more than one thing and return those? I know 
> that there are builtin functions for those parameters, but the point is 
> I want to define functions with more than one output.
> 
> The only examples I can find are along the lines of:
> 
> f[x_,y_]:=x^2+y^2;
> 
> which have only a single result.
> 
> Is there a different structure altogether, such as a Subroutine, which 
> allows multiple results from a single subunit?
> 
> One thought I had was that because Mathematica treats everything as 
> global unless defined specifically local (e.g. in a module), that 
> variables used in a procedure would be accessible and would thus be a 
> "result", but it seems scoping problems would arise if this was used too 
> often. For example:
> 
> In[67]:=
> t1[x_,y_]:=(a1=x^2+y;a2=x+y^2;x+y)
> 
> In[68]:=
> t2=t1[5,6]
> 
> Out[68]=
> 11
> 
> In[69]:=
> a1
> 
> Out[69]=
> 31
> 
> In[70]:=
> a2
> 
> Out[70]=
> 41
> 
> Is this the accepted method for extracting multiple results from one 
> function definition?
> 
> 
> Ben Barrowes
> 
> 


  • Prev by Date: Re: multiple outputs from a function
  • Next by Date: Re: multiple outputs from a function
  • Previous by thread: Re: multiple outputs from a function
  • Next by thread: Re: multiple outputs from a function