Re: Lists
- To: mathgroup at yoda.physics.unc.edu
- Subject: Re: Lists
- From: Boss Man <BOSS at noaapmel.gov>
- Date: Tue, 16 Mar 1993 14:14 PDT
Richard writes:
-----------------------------------
I am having a difficult time dealing with lists.
I have a list of data :
{{1,2},{2,3},{4,5}}
I want to do some operations on the second column only.
Such as +1, Sin[], etc to each element in the second
column. I admit I only have a rudimentary knowledge
of Map, Apply, Transpose, and Flatten. Any help would
be appreciated.
Also, I have data that needs several fitting equations.
One will be Exp[a x -b], another Exp[-c x+d], and the
last would be a polynomial. Then I would like to Plot
the data and fitting equations in there respective
regions at the same time. I have seen something
like this before, but I can't remember where.
Thanks
Richard
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Try using map and Transpose as in the following examples:
a = {{1,2},{2,3},{4,5}}
{{1, 2}, {2, 3}, {4, 5}}
b = Map[(# + 1)&, Transpose[a][[2]]]
{3, 4, 6}
c = Map[(Sin[#])&, Transpose[a][[2]]]
{Sin[2], Sin[3], Sin[5]}
It seems there must be a more elegant way to do this, but this
may get you started.
Ed Boss
NOAA/PMEL