num2strcell

function mystrcel=num2strcell(mynum,GFmat) % to convert a numeric array into a string cell % usage: %           mystrcel=num2strcell(YouNumArray,Digit.Format); %  e.g.,  mystrcel=num2strcell(0.1:0.1:0.5,'%3.2f'); %  copyright by http://scriptdemo.blogspot.com [nrow,ncol]=size(mynum); for nj=1:nrow       for ni=1:ncol             mystrcel{nj,ni}=num2str(mynum(nj,ni),GFmat);       end end

read netcdf file using native matlab functions

UPDATED VERSION:  Here function ncvardata=GetNcVarMatlab(ncfile,ncvar,RangeStr) % to read data from the netcdf file using native matlab netcdf-functions % Usage: vardata=GetNcVarMatlab(nc-filename,nc-varname,Dimension-Range) % e.g., % mydata=GetNcVarMatlab('mask.nc','tmask','1:1,1:46,1:400,1:568'); % RangeStr here is similar to the output of ncdump % copyright by http://scriptdemo.blogspot.com IsDebug=0; if ~exist(ncfile,'file')    error([ncfile,' can not been found']);    return end ncfid=netcdf.open(ncfile,'NC_NOWRITE'); % get dimension length [numdims, numvars, numglobalatts, unlimdimID] = netcdf.inq(ncfid); for NDim=1:numdims       [dimname{NDim}, dimlen(NDim)] = netcdf.inqDim(ncfid,NDim-1); end %var infor varid=netcdf.inqVarID(ncfid,ncvar); [varname,varxtype,vardimids,varnumatts]=netcdf.inqVar(ncfid,varid); numdims=length(vardimids); % some variables may have less dimensions if ~exist('RangeStr','var')    RangeStr=':';    for nd=2:numdims          RangeStr=[RangeStr,',:'];    end end IndC=strfind(RangeStr,',');% index of commas if length(IndC)~=numdims-1    disp(['Input dimension range is not correct, should be: ',num2str(numdims),'-d']);    return end startstr=''; countstr=''; stridestr=''; for nn=1:length(IndC)+1       if nn==1          tmpstr=RangeStr(1:IndC(1)-1);       elseif nn<numdims          tmpstr=RangeStr(IndC(nn-1)+1:IndC(nn)-1);       else          tmpstr=RangeStr(IndC(nn-1)+1:end);       end       [tmpstart,tmpcount,tmpstride]=GetIndFromStr(tmpstr,':',dimlen(vardimids(numdims-nn+1)+1));      if nn==1         startstr=[num2str(tmpstart),'],'];         countstr=[num2str(tmpcount),'],'];         stridestr=[num2str(tmpstride),']'];      elseif nn==numdims         startstr=[',[',num2str(tmpstart),',',startstr];         countstr=['[',num2str(tmpcount),',',countstr];         stridestr=['[',num2str(tmpstride),',',stridestr];      else         startstr=[num2str(tmpstart),',',startstr];         countstr=[num2str(tmpcount),',',countstr];         stridestr=[num2str(tmpstride),',',stridestr];      end end if IsDebug    disp(['ncvardata=netcdf.getVar(ncfid,varid',startstr,countstr,stridestr,');']); end eval(['ncvardata=netcdf.getVar(ncfid,varid',startstr,countstr,stridestr,');']); netcdf.close(ncfid); ncvardata=permute(ncvardata,length(size(ncvardata)):-1:1); function [numstart,numcount,numstride]=GetIndFromStr(tmpstr,ctag,Ndim) % Read the numbers from the special string IsDebug=0; IndC=strfind(tmpstr,ctag); if isempty(IndC)    numstart=str2double(tmpstr)-1;    numcount=1;    numstride=1; else   switch length(IndC)     case {1}         switch IndC             case {1} % : and :num                 if strcmp(tmpstr,':')                    numstart=0; numcount=Ndim; numstride=1;                 else                    if strcmp(tmpstr(2:end),'end')                       numstart=0; numcount=Ndim; numstride=1;                    else                       numstart=0; numcount=str2double(tmpstr(2:end))-1; numstride=1;                    end                 end             case {length(tmpstr)}                 if strcmp(tmpstr,':')                     numstart=0; numcount=Ndim; numstride=1;                     return                 else                     numstart=str2double(tmpstr(1:IndC-1))-1;                     numcount=Ndim-numstart;                     numstride=1;                 end            otherwise                 numstart=str2double(tmpstr(1:IndC-1))-1;                 if strcmp(tmpstr(IndC+1:end),'end')                     numend=Ndim;                 else                     numend=str2double(tmpstr(IndC+1:end));                 end                 numcount=numend-numstart;                 numstride=1;             end    case {2}       % num0:stride:num1       if IndC(1)==1          numstart=0;       else          numstart=str2double(tmpstr(1:IndC(1)-1))-1;       end       if IndC(2)==IndC(1)+1          numstride=1;       else          numstride=str2double(tmpstr(IndC(1)+1:IndC(2)-1));       end       if IndC(2)==length(tmpstr)              numend=Ndim;       else          if strcmp(tmpstr(IndC(2)+1:end),'end')             numend=Ndim;          else             numend=str2double(tmpstr(IndC(2)+1:end));          end       end       numcount=numend-numstart;    otherwise        error('Not defined range type')    end end if IsDebug    disp(['tmpstr=',tmpstr])    disp(['start:',num2str(numstart), ' stride:',num2str(numstride),' count:',num2str(numcount)]) end

Visualize Julia Sets using Matlab

function myjulia(Zmax,c,N) % Generate and visualize quadratic Julia Sets % More information about Julia Sets can be found here: % http://en.wikipedia.org/wiki/Julia_set % this code is for the assignment of the "Introduction to Matlab" offered by MITOPENCOURSEWARE % Coded by http://scriptdemo.blogspot.com if (nargin==1)    Ndemo=Zmax; clear Zmax    switch Ndemo    case {1}        myjulia(1,-0.297491+i*0.641051,100);        return;    case {2}        myjulia(0.35,-0.297491+i*0.641051,250);        return;    otherwise       disp('Not defined demo type!')       help myjulia;       return    end elseif (nargin~=3)    help myjulia;    return end % generate the basic matrix NM=500; [Z,tmpy]=meshgrid(linspace(-Zmax,Zmax,NM),zeros(1,NM)); Z=Z+i*Z'; clear tmpy % compute the escape velocity myM=reshape(escapeVelocity(Z(:),c,N),NM,NM); % visualize the results imagesc(atan(0.1*myM)); figurenicer;axis xy; function n=escapeVelocity(z0,c,N) n=z0*0; NLen=length(z0); IndZ=1:length(z0); IndZ=IndZ'; for ni=1:N       IndLT=find(abs(z0)<2);       IndGE=find(abs(z0)>=2);       n(IndZ(IndGE))=ni;       if (length(IndLT)>0)          z0(IndLT)=z0(IndLT).*z0(IndLT)+c;       end       z0(IndGE)=[];       IndZ(IndGE)=[]; end if ~isempty(IndZ)    n(IndZ)=N; end

myjulia(2)

Generate a series of column names in R

#if you want a series of column names, e.g., col1,col2,col3, ..., #you can use: mydf<-data.frame(matrix(ncol=5,nrow=4)) colnames(mydf)<-c("col1","col2","col3","col4","col5") #Well, it does work, but how about for 50 columns? #A loop! Sounds great. Okay, mydf<-data.frame(matrix(ncol=50,nrow=4)) for (n in 1:ncol(mydf)) {       colnames(mydf)[n]<-paste("col",n,sep="") } #But again, it's as urgly as the textbook. Here we offer a much better solution: colnames(mydf)<-paste(rep("col",ncol(mydf)),c(1:ncol(mydf)),sep="") #Smart, eh? At least the nicer looking :) #From http://scriptdemo.blogspot.com

Trim a string in R

# sub-functions # Copyright: http://scriptdemo.blogspot.com mytrim<-function(oristr) {      oristr<-sub("^ +","",oristr)      oristr<-sub(" +$","",oristr)      # or gsub("(^ +)|( +$)","",oristr)      return(oristr) }