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MathGroup Archive 2006

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RE: List Manipulation

  • To: mathgroup at
  • Subject: [mg72432] RE: [mg72407] List Manipulation
  • From: "David Park" <djmp at>
  • Date: Wed, 27 Dec 2006 06:27:23 -0500 (EST)

Two methods...

list = {a1 + b1*k, a2 + b2*k, a3 + b3*k};

{Alist, Blist} = list /. a_ + b_  k -> {a, b} // Transpose
{{a1, a2, a3}, {b1, b2, b3}}

{Alist, Blist} = CoefficientList[#, k] & /@ list // Transpose
{{a1, a2, a3}, {b1, b2, b3}}

David Park
djmp at

From: Stratocaster [mailto:stotz1 at]

I'm not sure if the following is possible or whether it exists somewhere
between the realms of fantasy and science fiction.  I have been unable to do

Given a list, set, vector (whatever you want to call it) consisting of
functions of the same variable, i.e.

list = {a1+b1*k, a2+b2*k, a3+b3*k...}

Assuming they are all linear (of the form a+b*k) is there away to isolate
the a_i and b_i values?  Essentially I would like to get a list "A"
consisting of all the intercept values, and a list "B" consisting of all the
slope values.

Is this possible?  What kind of operations do I need to use to accomplish
this (if indeed it is possible)?

Thanks for any insights.

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