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Re: A question about pattern-matching

• To: mathgroup at smc.vnet.net
• Subject: [mg63754] Re: [mg63728] A question about pattern-matching
• From: ggroup at sarj.ca
• Date: Fri, 13 Jan 2006 04:48:44 -0500 (EST)
• References: <djcgcs$6du$1@smc.vnet.net> <200510230946.FAA10826@smc.vnet.net> <200601120822.DAA10486@smc.vnet.net>
• Reply-to: ggroup at sarj.ca
• Sender: owner-wri-mathgroup at wolfram.com

On Thursday, January 12, 2006 at 03:22 GMT -0500, Gardyloo wrote:

<snip>
> First, a small subset of the data:

> testList = {{-90, {{60493, 0.061}, {62493, 0.15881}, {64493.5, 

>             0.559}}}, {-88, {{62493, 0.151}, {64493., 0.61617}, {65993.4, 

>             0.171}, {68993.10, 0.06}}}, {-86, {{62493.75, 0.14}, {64493.55, 

>             0.61440}, {65993., 0.18}, {67993, 0.0}, {68993.100, 0.06448}}}};


> The data consists of lists of the form  { integer, {  ordered pair1,
> ordered pair2, ... } }, and my goal is to extract the second number in
> each of the ordered pairs, while retaining the lists' overall structure.

What about using Part?  I think you get exactly what you want with:
testList[[All,2,All,2]]

> So, for example, from testList, I'd want something like
>       { { 0.061, 0.15881, 0.559}, {0.151, 0.61617, 0.171, 0.06}, {0.14,
> 0.61440, 0.18,  0.0, 0.06448}}
> returned.

In[1]:= testList = {{-90, {{
    60493, 0.061}, {
        62493, 0.15881}, {64493.5, 0.559}}}, {-88, {{62493, 0.151}, {64493., 
          0.61617}, {65993.4, 0.171}, {68993.10, 
      0.06}}}, {-86, {{62493.75, 0.14}, {64493.55, 
          0.61440}, {65993., 0.18}, {67993, 0.0}, {68993.100, 0.06448}}}};

In[2]:= testList[[All, 2, All, 2]]
Out[2]= {{0.061, 0.15881, 0.559}, {0.151,
    0.61617, 0.171, 0.06}, {0.14, 0.6144, 0.18, 0., 0.06448}}

In[3]:= %=={{0.061, 0.15881, 0.559}, {0.151, 0.61617, 0.171, 0.06}, {0.14,
    0.61440, 0.18, 0.0, 0.06448}}
Out[3]= True

• References:
  • A question about pattern-matching
    • From: gardyloo <gardyloo@mail.wsu.edu>