Re: working with nested lists

• To: mathgroup at smc.vnet.net
• Subject: [mg127713] Re: working with nested lists
• From: Bob Hanlon <hanlonr357 at gmail.com>
• Date: Thu, 16 Aug 2012 01:57:57 -0400 (EDT)
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• Delivered-to: l-mathgroup@wolfram.com
• Delivered-to: mathgroup-newout@smc.vnet.net
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• References: <20120815073426.2CC1E684B@smc.vnet.net>

```"Unless an explicit Return is used, the value returned by Do is Null."

myList = {{{-33.355 Degree, 278.265}, {-33.486 Degree,
155.871}, {-60.650 Degree, 27.534}}, {{-38.418 Degree,
148.054}, {-165.173 Degree, 70.342}}};

m1 = Table[
Table[{myList[[k, i, 1]],
myList[[k, i, 2]] (-1)/Sin[myList[[k, i, 1]]]},
{i, Length[myList[[k]]]}],
{k, Length[myList]}];

m2 = ((# /. {a_, b_?NumericQ} -> {a, -b*Csc[a]}) & /@ myList);

m3 = Map[{#[[1]], -#[[2]]*Csc[#[[1]]]} &, myList, {2}];

m1 === m2 === m3

True

Bob Hanlon

On Wed, Aug 15, 2012 at 3:34 AM, Levente <lemonlev at mac.com> wrote:
> I'm trying to apply a transformation to a every element in a nested list. The issue is that each sub-list has a different length
>
> Example of the list:
> myList={{{-33.355 Degree, 278.265}, {-33.486 Degree,
>   155.871}, {-60.650 Degree, 27.534}},
> {{-38.418 Degree, 148.054}, {-165.173 Degree, 70.342}}};
>
> This is what I am trying and does not work:
> Do[
>  Table[{myList[[k, i, 1]], myList[k, i, 2]] (-1)/Sin[myList[[k, i, 1]]]}, {i,
>    Length[myList[[k]]]}], {k, Length[myList]}]
>
> Any tips?
>

```

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