Summing elements within a List or Array

• To: mathgroup at smc.vnet.net
• Subject: [mg69524] Summing elements within a List or Array
• From: "John Adeosun" <jtadeosun at yahoo.com>
• Date: Thu, 14 Sep 2006 06:57:15 -0400 (EDT)
• Organization: Stevens Institute of Technology (stevens-tech.edu)

```Hello Everyone,

I generated an intended list of real numbers using Mathematica 5.2, say
"alist", that looks like:

alist = {{0}, {{1.2},0}, {{2.3},{1.2},0},{{3.4},{2.3},{1.2},0},
................{{99.0},{98.9},{97.8},.......,0}}
(In Matrix form, this "alist" can be shown as a LowerDiagonal Matrix)

Meanwhile, my present goal is to then program using Mathematica to obtain a
list, say "aalist", having each element equal to the sum of the elements in
each(corresponding) sublist of the original list "alist." That is,

aalist  = {0, 1.2, 3.5, 6.9,...........}

In essence, it is like reducing, say, 100 by 100 matrix to 100 by 1 matrix
via summing operation.

I programmed using some summing operations/functions in Mathematica to no
avail. I don't know what I 'm doing wrong.

Can anyone help with this problem?

Thanks,

John.

```

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