Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

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

Search the Archive

Re: Creating a new table using values from a column in another table,

  • To: mathgroup at smc.vnet.net
  • Subject: [mg66365] Re: Creating a new table using values from a column in another table,
  • From: Peter Pein <petsie at dordos.net>
  • Date: Thu, 11 May 2006 02:14:07 -0400 (EDT)
  • References: <e3sgqp$lsf$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Wonko the Sane schrieb:
> Hi all,
> 
> I have a question that I have not been able to work out myself, and so 
> put it to the group to help. I have a set of data points in a table (2 
> columns {{x1,y1},{x2,y2},....,{xn,yn}}) I have performed a fit to the 
> data and have a function f[x] which I would now like to evaluate at each 
> data point (column 1 of the first table) to get a new table 
> {{x1,f[x1]},{x2,f[x2]},....,{xn,f[xn]}}. Is there a way to do this? I 
> hope my request is clear
> 
> Best Regards
> Michael
> 

Coose one (there are most propably more possibilities):

data = Table[ToExpression[StringJoin[#1, ToString[n]]]& /@ {"x", "y"}, {n, 5}]
--> {{x1, y1}, {x2, y2}, {x3, y3}, {x4, y4}, {x5, y5}}

{#1, f[#1]}& /@ First /@ data
--> {{x1, f[x1]}, {x2, f[x2]}, {x3, f[x3]}, {x4, f[x4]}, {x5, f[x5]}}

Transpose[{#1, f /@ #1}&[First[Transpose[data]]]]
--> {{x1, f[x1]}, {x2, f[x2]}, {x3, f[x3]}, {x4, f[x4]}, {x5, f[x5]}}

data /. {x_?AtomQ, _} :> {x, f[x]}
--> {{x1, f[x1]}, {x2, f[x2]}, {x3, f[x3]}, {x4, f[x4]}, {x5, f[x5]}}

Peter


  • Prev by Date: Re: Creating a new table using values from a column in another table,
  • Next by Date: Re: Mathematica Question
  • Previous by thread: Re: Creating a new table using values from a column in another table,
  • Next by thread: Re: Creating a new table using values from a column in another table,