Re: Iterate Through a List

• To: mathgroup at smc.vnet.net
• Subject: [mg77367] Re: Iterate Through a List
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Thu, 7 Jun 2007 03:56:41 -0400 (EDT)
• Organization: Uni Leipzig
• References: <f4697t\$3ps\$1@smc.vnet.net>

```Hi,

try

First /@ MyListLooksLike

Regards
Jens

Nick wrote:
> Hello! I'm (somewhat) new to Mathematica and I  need help to iterating
> through a list and counting the occurrence of a number.
>
> My list looks like:
>
> {{1,0},{1,1},{2,x+x^2+x^4},{2,1+x+x^2+x^4},{4,x+x^2},{4,1+x+x^2},{4,x+
> \
> x^4},{4,1+x+x^4},{4,x^2+x^4},{4,1+x^2+x^4},{4,x^3+x^4},{4,1+x^3+x^4},
> {\
> 4,x+x^2+x^3+x^4},{4,1+x+x^2+x^3+x^4},{5,x+x^3},{5,1+x+x^3},
> {5,x^2+x^3}\
> ,{5,1+x^2+x^3},{5,x+x^3+x^4},{5,1+x+x^3+x^4},{5,x^2+x^3+x^4},{5,1+x^2+
> \
> x^3+x^4},{8,x},{8,x^2},{8,x^3},{8,x^4},{8,1+x},{8,1+x^2},{8,1+x^3},
> {8,\
> x+x^2+x^3},{8,1+x+x^2+x^3},{8,1+x^4}}
>
> The number that I would need to keep track of is the first in each sub-
> list.
>
> So for the first couple {{1,0},{1,1},{2,x+x^2+x^4},{2,1+x+x^2+x^4},{4,x
> +x^2},........
>
> I would need to keep track of 1,1,2,2,4........
>
> It will not always be 1,2,4,5,8's.  The numbers may be completely
> different on each pass.  Each sublist may be composed of more items
> but the number that I need to keep track of will always be the 1st in
> the sub-list.  Any help or suggestions that you can give me will be
> greatly appreciated.  Thanks so much!
> -Nick
>
>

```

• Prev by Date: Re: pure function to generate a list of integrals
• Next by Date: Re: Best practice for Mathematica package development
• Previous by thread: Iterate Through a List
• Next by thread: Re: Iterate Through a List