Re: What is f[1]? Advanced question
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- Subject: [mg131315] Re: What is f[1]? Advanced question
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Thu, 27 Jun 2013 06:32:35 -0400 (EDT)
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On 6/25/13 at 9:14 PM, Anthony.J.Mannucci at jpl.nasa.gov (amannucci)
wrote:
>I have found a Mathematica program with the following construct:
>x[1]=0.1
>x[2]=0.2
>x[3]=0.3
>or Do[x[i]=i/10.,{i,1,3}]
>x is not a function. It is not a list. What is it?
x is a function that you have defined at specific values.
Notice that
In[1]:= x[1] = 0.1;
x[2] = 0.2;
x[3] = 0.3;
In[4]:= DownValues[x]
Out[4]= {HoldPattern[x(1)]:>0.1,HoldPattern[x(2)]:>0.2,HoldPattern[x(3)]:=
>0.3}
and
In[5]:= f[y_] := y^2
In[6]:= DownValues[f]
Out[6]= {HoldPattern[f(y_)]:>y^2}
That is the values for x are stored exactly like the definition
of an expression is what most think of as a function in Mathematica.