       Re: take square of the second and third column of a table

• To: mathgroup at smc.vnet.net
• Subject: [mg124191] Re: take square of the second and third column of a table
• From: Barrie Stokes <Barrie.Stokes at newcastle.edu.au>
• Date: Thu, 12 Jan 2012 04:20:01 -0500 (EST)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <201201112220.RAA22144@smc.vnet.net>

```Hi

I like to use code that I think is explicit, i.e., I can see what I was doing when I read my code in 6 months time.

A = {{a, b, c}, {d, e, f}, {g, h, i}, {j, k, l}}

A // Column

B = Table[{A[[n]][], A[[n]][]^2, A[[n]][]^2}, {n, 1, 4}]

Map[ (s \[Function] {
\!\(\*SubscriptBox[\(s\), \(\(\[LeftDoubleBracket]\)\(1\)\(\ \)\(\
\[RightDoubleBracket]\)\)]\),
\!\(\*SubscriptBox[\(s\), \(\(\[LeftDoubleBracket]\)\(\ \)\(2\)\(\ \)\
\(\[RightDoubleBracket]\)\)]\)^2,
\!\(\*SubscriptBox[\(s\), \(\(\[LeftDoubleBracket]\)\(\ \)\(3\)\(\ \)\
\(\[RightDoubleBracket]\)\)]\)^2}), A ]

Barrie

PS
Always a bad idea to use capitals for or as the first character of your variables; try C = 34.

>>> On 12/01/2012 at 9:20 am, in message <201201112220.RAA22144 at smc.vnet.net>,
hanciong awesome <hanciong at gmail.com> wrote:
> Hello, suppose I have a very long table like this:
>
> 1 2 3
> 4 5 6
> 7 8 9
> .......
> 2 3 4
>
> how can I take square of the 2nd and 3rd column? I always do it by
> making a new table. so let's say the above table is A and it has 100
> lines, then I make the new table as the following:
>
> B=Table[{A[[n]][],A[[n]][]^2,A[[n]][]^2},{n,1,100}]
>
> But if the length of the table is unknown, this way is impractical.
> Could anyone suggests better way? thank you

```

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