MathGroup Archive 2009

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: problem of syntax.

  • To: mathgroup at
  • Subject: [mg104370] Re: problem of syntax.
  • From: David Bailey <dave at>
  • Date: Thu, 29 Oct 2009 02:58:07 -0500 (EST)
  • References: <hc91nu$e3r$>

micmac wrote:
> Hello everyone,
> For some reasons, I have a matrix where each element is itself another
> matrix of size one.
> How can I transform that in a normal matrix where each element is just the
> value ?
> I am very confused with mathematica syntax.
> thanks,
> Julien
Given a nested list structure such as you describe, probably the easiest 
way to transform it is with Map:

In[6]:= start = {{{10}, {20}}, {{30}, {40}}};

In[13]:= Map[First, start, {2}]

Out[13]= {{10, 20}, {30, 40}}

Maybe the real question you need to ask is how you got that structure in 
the first place - you say "for some reasons". Tell us how you got there 
and we can fix your real problem!

Regarding Mathematica syntax, I would strongly recommend spending a few 
hours exploring the syntax before plunging into solving a specific 
problem of your own. Try the tutorials and/or type "lists" into the help 
system, and follow the various tutorial-style links such as 
"constructing lists". Remember that you can cut and paste the help 
examples into a notebook of your own. If you do this, you will quickly 
build up a collection of recipes to help you with your own work. 
Mathematica syntax is extremely logical and easy to use even if it 
appears hard at first - so persevere a bit. If all else fails, go on a 
short course.

David Bailey

  • Prev by Date: Re: SetterBar/ButtonBar, Dynamic and the visual appearance of "selected"
  • Next by Date: Re: old vs new(V7) BarChart3D
  • Previous by thread: Re: problem of syntax.
  • Next by thread: Re: problem of syntax.