Re: Adding a value to the cell of a matrix

*To*: mathgroup at smc.vnet.net*Subject*: [mg75903] Re: [mg75880] Adding a value to the cell of a matrix*From*: DrMajorBob <drmajorbob at bigfoot.com>*Date*: Sun, 13 May 2007 05:42:16 -0400 (EDT)*References*: <2868213.1178958082081.JavaMail.root@m35>*Reply-to*: drmajorbob at bigfoot.com

Never, EVER use do loops. (OK, sometimes. As a last resort.) any = Table[RandomReal[], {i, 5}, {j, 4}]; gt0 = Map[If[# > 1/2, 1, 0] &, any, {2}] {{0, 0, 1, 1}, {1, 1, 1, 1}, {0, 0, 1, 0}, {1, 0, 1, 0}, {1, 0, 0, 1}} (1 indicates a number > 1/2, 0 otherwise.) This counts occurrences by column: Plus @@ gt0 {3, 1, 4, 3} or Total /@ Transpose[gt0] {3, 1, 4, 3} Counting by row: Total /@ gt0 {2, 4, 1, 2, 2} Bobby On Sat, 12 May 2007 02:15:03 -0500, newbie <puretexan at gmail.com> wrote: > I have a matrix of values that i am searching for a specific value in > and i want to count the number of occurances in each column. which i > can do but not in a loop. I want to be able to use a matrix to store > the number of occurances so i can put it in a loop. I already have a > loop that finds the values and just adds them to a value i created. do > you know how i can add +1 to the cell of a matrix? When i try to do > this it says the values are protected. i tried unprotecting them but > couldn't get that to work. > > > any ideas? > > Here is the code i am using for the search > > > In[673]:=Orderedcellcycle=OverExpressed; (* Dimensions {200, 18}*) > l=matrix1; (*{5164, 18}*) > Do[l[[All,i]]=Ordering[matrix1[[All,i]]],{i,1,18}]; > Do[Do[Orderedcellcycle[[i,j]]=annotations[[l[[i,j]],6]],{i,1,200}],{j, > 1,18}]; > > In[678]:=gcounter=scounter=gmcounter=mgcounter=sgcounter=0; > > In[679]:=Do[Do[If[Orderedcellcycle[[i,j]]=="G1",gcounter=gcounter > +1,gcounter=\ > gcounter+0],{i,1,200}]; > Do[If[Orderedcellcycle[[i,j]]=="S",scounter=scounter+1,scounter= > scounter+0],{i,1,200}]; > Do[If[Orderedcellcycle[[i,j]]=="S/G2",sgcounter=sgcounter > +1,sgcounter= > sgcounter+0],{i,1,200}]; > Do[If[Orderedcellcycle[[i,j]]=="G2/M", > gmcounter=gmcounter+1,gmcounter=gmcounter+0],{i,1,200}]; > Do[If[Orderedcellcycle[[i,j]]=="M/G1",mgcounter=mgcounter > +1,mgcounter= > mgcounter+0],{i,1,200}],{j,1,18}] > > > -- DrMajorBob at bigfoot.com