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Dwight, the For command must use uppercase F. Secondly, the nf<=Nfrq+1 yields a value of 11 but frg has a maximum of 10 elements. This requires nf<Nfrq + 1 or nf,<=Nfrq. Hope this helps. Regards, -Ed

Thanks for all the good help. I was able to get started using the following simple: ae = Table[0, {Nd}]; Zae = Table[0, {Nd}]; Zbe = Table[0, {Nd}]; For[Nd = 1, Nd < Necc + 1, Nd++, g = gap[[Nd]]; Da = 2 ra 1000; Db = 2 rb 1000; ae[[Nd]] = (g (Db - g) (Db - Da - g) (Da + g))^0.5 /(Db - Da - 2 g); Zae[[Nd]] = ArcSinh[2 ae[[Nd]] /Da]; Zbe[[Nd]] = ArcSinh[2 ae[[Nd]] /Db]; a = ae[[Nd]] /1000; Za = Zae[[Nd]]; Zb = Zbe[[Nd]]; ];

and this works. But then I try using the same here: frq1 = 50 10^6; frq2 = 1000 10^6; Nfrq = 95; frq = Table[0, {Nfrq}]; for [Nf = 1, Nf < Nfrq + 1, Nf++, frq[[Nf]] = frq1 + (Nf - 1) (frq2 - frq1)/Nfrq; ];

and it does not work. Any idea why this does not work?

Here is a List:

myList = {{a, b, c}, {d, e, f}, {g, h, i}}

To access the 3rd element of the 2nd row, i.e. [2,3]:

myList[[2,3]]

More details can be found in the doucmentation at http://reference.wolfram.com/language/ref/Part.html

This tutorial on Lists should help as well: http://reference.wolfram.com/language/tutorial/ListsOverview.html