ConstantCoefficient of polynomial

• To: mathgroup at smc.vnet.net
• Subject: [mg3368] ConstantCoefficient of polynomial
• From: wagner at bullwinkle.cs.Colorado.EDU (Dave Wagner)
• Date: Sat, 2 Mar 1996 04:13:27 -0500
• Organization: University of Colorado, Boulder
• Sender: owner-wri-mathgroup at wolfram.com

Whoops, a following to my previous post about finding the constant
coefficient of a polynomial.  I proposed:

In[1]:=
ConstantCoefficient[poly_Plus] := Select[poly, NumberQ[N[#]]&]

In[3]:=
ConstantCoefficient[E^2 + Pi + Sqrt[7]x + Sqrt[5]]
Out[3]=
2
Sqrt[5] + E  + Pi

which works fine as long as there IS a constant coefficient.
If not, it does not evaluate (by design):

In[8]:=
ConstantCoefficient[Sqrt[7]x]
Out[8]=
ConstantCoefficient[Sqrt[7] x]

This is easily handled by specifying a "catch-all" case that returns 0:

In[9]:=
ConstantCoefficient[_] := 0
In[10]:=
ConstantCoefficient[Sqrt[7]x]
Out[10]=
0

Dave Wagner
Principia Consulting
(303) 786-8371
dbwagner at princon.com
http://www.princon.com/princon

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