Re: Count Function

*To*: mathgroup at smc.vnet.net*Subject*: [mg65521] Re: [mg65501] Count Function*From*: János <janos.lobb at yale.edu>*Date*: Thu, 6 Apr 2006 06:52:04 -0400 (EDT)*References*: <200604051055.GAA21742@smc.vnet.net> <55DC5ED6-AB89-4A5A-B93F-694BAD259CF6@yale.edu> <04811363-653A-423F-8283-C2FF31B1BAD2@videotron.ca>*Sender*: owner-wri-mathgroup at wolfram.com

Gregory, As I see, Count wants a form or a pattern describing the appearance of an element or the element be in a Wolfram defined domain. I do not see how a criteria like being bigger than -9 can be encapsulated into an appearance. When you do Count[xx[[All,14]],-9.] it is giving you NOT who EQUALs to -9 but rather who LOOKs LIKE -9. For me that is two different things. Of course it does not mean that someone else cannot do it :) Here is my second newbie approach, in this case using Count: Count[(#1 > 9 & ) /@ xmat[[All,14]], True] It is still a combo. It is a little slower for small lists then the Length[Select[...]] combo. With the best, János On Apr 5, 2006, at 1:00 PM, Gregory Lypny wrote: > Thanks János, > > That would be my natural inclination: to combine two functions, > Length and Select in this case, to get a result that serves as a > check of whatever I'm able to hammer out directly using something > like Count. > > Regards, > > Gregory > > On Wed, Apr 5, 2006, at 12:47 PM, János wrote: > >> >> On Apr 5, 2006, at 6:55 AM, Gregory Lypny wrote: >> >>> The syntax will be the death of me. >>> >>> Count[X[[All,14]], -9.] will tally how many elements in column 14 of >>> matrix X are equal to -9, but I can't for the life of me figure out >>> how to get how many are greater than -9. Any hint would be most >>> appreciated. >>> >>> Greg >>> >> >> Here is a newbie approach: >> >> In[1]:= >> xmat = Table[Table[ >> Random[Integer, >> {1, 100}], {i, 1, 20}], >> {j, 1, 30}] >> >> >> In[6]:= >> Length[Select[xmat[[All,14]], >> #1 > 9 & ]] >> Out[6]= >> 25 >> >> >> János >> >> >> ---------------------------------------------- >> Trying to argue with a politician is like lifting up the head of a >> corpse. >> (S. Lem: His Master Voice) >> ---------------------------------------------- Trying to argue with a politician is like lifting up the head of a corpse. (S. Lem: His Master Voice)

**References**:**Count Function***From:*Gregory Lypny <gregory.lypny@videotron.ca>