Mathematica 9 is now available
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: Conditions with Statistical Functions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg66169] Re: Conditions with Statistical Functions
  • From: Gregory Lypny <gregory.lypny at videotron.ca>
  • Date: Tue, 2 May 2006 02:43:44 -0400 (EDT)
  • References: <16568608.1146308002406.JavaMail.root@eastrmwml01.mgt.cox.net> <e31vb8$hgd$1@smc.vnet.net> <4454EC45.8030009@gmail.com>
  • Sender: owner-wri-mathgroup at wolfram.com

Thanks again, Jean-Marc.

This is elegant.  As I mentioned before, I'm facing an uphill battle  
with Mathematica's syntax, and in particular, the meaning and  
placement of things like #, #1, or #[[1]], &, @, @@, @@@, /@, /. .   
It's all a bit overwhelming!

I think I understand your second version better, so I'll work with it  
first.  If I'm not mistaken, /@ tells the Mean function to map over  
its argument and #1 directs that mapping to the first argument, which  
for Mean applied to a matrix is a vector.  What I never would have  
gotten on my own is the use of the second ampersand in parenthesis.   
Is that meant to connect Select with Transpose?  I'm also not quite  
clear on why we need Transpose because Mean operates on columns anyway.

Regards,

	Greg


On Sun, Apr 30, 2006, at 12:56 PM, Jean-Marc Gulliet wrote:

> In[3]:=
> Mean /@ (Transpose[lst /. x_ /; x <= 100 -> 0] /.
>    0 -> Sequence[])
>
> Out[3]=
>       1311  1450  527
> {125, ----, ----, ---}
>        8     9     3
>
> In[4]:=
> Mean /@ (Select[#1, #1 > 100 & ] & ) /@ Transpose[lst]
>
> Out[4]=
>       1311  1450  527
> {125, ----, ----, ---}
>        8     9     3
>
> Best regards,
> Jean-Marc



  • Prev by Date: puzzling mathworld formulas
  • Next by Date: Re: Illusory Multicore Support in 5.2?
  • Previous by thread: Re: Conditions with Statistical Functions
  • Next by thread: Re: Conditions with Statistical Functions