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) }

Run matlab m-file in a shell script

It is common to run Matlab without splash and desktop using the following command,         matlab -nosplash -nodesktop Sometime the "-nojvm" option also help to reduce the memory requires if the java-virtual-mathine features are not necessary in your script. But, what should we do if we want to run a Matlab m-file in a shell script? The only thing we need is the option of "-r",         matlab -nosplash -nodesktop -r YourMFile However, sometimes it will be much more convenient if we can run the function-type m-file with arguments. Here it comes today's tricky stuff:                matlab -nodesktop -nosplash -r YourMFile\(Number,\'character\'\) Matlab Start Help

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Here is an example,
runMatlabScript.sh

#!/bin/bash myNum=30 myT="Demo\ of\ Peaks\(${myNum}\)" myPNG="fig_peaks_${myNum}" eval "/media/SW_Preload/matlab/bin/matlab -nodesktop -nosplash -r showPeaks\(${myNum},\'${myT}\',\'${myPNG}\'\)"

showPeaks.m:

function showPeaks(myN,myTitle,myPNG) % show the the peaks % usage: %           showPeaks(N,Title,FileName) %           http://scriptdemo.blogspot.ca if nargin~=3    disp('Usage: ')    disp(' showPeaks(N,Title,FileName) ')    return end hf=figure('visible','off'); set(hf,'color','w','render','zbuffer'); hp=pcolor(peaks(myN)); set(hp,'linestyle','none'); title(myTitle,'fontweight','bold','fontsize',16); set(gca,'linewidth',2) eval(['print -dpng -r300 ',myPNG,'.png']) close; exit

An example of image processing using matlab

function [imgdatadb,mymask]=rgb2whiteblack(ImgFileName,mymask) %  To show some basic image processing (percentage of some colors) %  using matlab. Also shows how to create a mask using mouse. %  Copyright: http://scriptdemo.blogspot.com IsFig=0; IsFinalFig=1; % read image if nargin==0     ImgFileName='8x.JPG'; end if ~exist(ImgFileName,'file')     disp(['image file: ',ImgFileName,' cannot be found!!! return nothing'])     imgdatadb=[];mymask=[];     return end % assume input image is in rgb mode imgrgb=imread(ImgFileName); % Be more accurate or professional, consider operations with rgb channels if ~exist('mymask','var')    %create the mask    mask1=roipoly(imgrgb);    mask2=roipoly(imgrgb);    mask3=roipoly(imgrgb);    mymask=mask1+mask2+mask3;    close; end if IsFig % show rgb channels of the image    figure;    for N=1:4        subplot(2,2,N);        if N~=4           imagesc(imgrgb(:,:,N));        else           imagesc(imgrgb);        end    end end % convert data into gray scale [intensity image] imgdata=rgb2gray(imgrgb); % or maybe consider rgb2bw %convert to double imgdatadb=double(imgdata); % convert dark part to black imgdatadb(imgdatadb<100)=0; % ..      light part to white imgdatadb(imgdatadb>=100)=255; % set mask region to specified value, e.g., 90 imgdatadb(mymask==1)=90; % statistics NumOfMaskP=length(find(mymask==1)); NumOfEffectiveP=length(imgdatadb(:))-NumOfMaskP; PerEffective=NumOfEffectiveP/(NumOfMaskP+NumOfEffectiveP)*100; PerBlack=length(find(imgdatadb==0))/NumOfEffectiveP*100; % show percentage disp(['Percentage of Effective  pixels (%): ',num2str(PerEffective)]) disp(['Percentage of black region (%): ',num2str(PerBlack)]) % show image if IsFinalFig    figure;    title('Origin Gray image');imagesc(imgdata);    figure;    title('Black and White'); imagesc(uint8(imgdatadb)); end

Plot a heart curve in matlab

 

function ShowHeart(Ntype) % a funny script to show different kind of heart curves % Usage: %        ShowHeart() % Copyright: http://scriptdemo.blogspot.com % Ref: http://www.mathematische-basteleien.de/heart.htm %        http://mathworld.wolfram.com/HeartCurve.html if nargin==0 Ntype=1; end np=999;Is3D=0;IsFilled=1; switch Ntype     case {1}        t=0:2*pi/np:2*pi;        xx=(1-sin(t)).*cos(t);        yy=(1-sin(t)).*sin(t);     case {2}        t=-1:2/(np*100):1;        xx=sin(t).*cos(t).*log(abs(t));        yy=sqrt(cos(t)).*abs(t).^0.3;        yy(isnan(xx))=[];        xx(isnan(xx))=[];     case {3}        t=-1:2/(np*100):1;        xx=sin(t).*cos(t).*log(abs(t));        yy=sqrt(abs(t)).*cos(t);        yy(isnan(xx))=[];        xx(isnan(xx))=[];     case {4}        t=0:2*pi/np:2*pi;        r=sin(t).*sqrt(abs(cos(t)))./(sin(t)+7/5)-2*sin(t)+2;        xx=r.*cos(t); yy=r.*sin(t); clear r     case {5}        t=0:60/np:60;        r=0.01*(-t.*t+40*t+1200);        xx=r.*sin(pi*t/180);        yy=r.*cos(pi*t/180); clear r t        xx=[xx fliplr(-xx)]; yy=[yy fliplr(yy)];     case {6}        t=-1:2/(np*100):1;        r=(1-abs(t)).*(1+3*abs(t));        xx=r.*sin(t); yy=r.*cos(t); clear r t     otherwise        disp(['Sorry, you just broke my heart!']);        Is3D=1;        t=0:2*pi/np:2*pi;        r=sin(t).*sqrt(abs(cos(t)))./(sin(t)+7/5)-2*sin(t)+2;        xx=r.*cos(t); yy=r.*sin(t); clear r end if ~Is3D    if ~IsFilled       plot(xx,yy,'color','r');    else       hf=fill(xx,yy,'r');set(hf,'linestyle','none');    end else   hp=plot(xx,yy,'g');set(hp,'linestyle','none');   figurenicer; hold on;   myxlim=xlim;myylim=ylim;   nrp=50;   nxgrid=20;   nygrid=20;   xxn=linspace(myxlim(1),myxlim(2),nxgrid);   yyn=linspace(myylim(1),myylim(2),nygrid);   [xxn,yyn]=meshgrid(xxn,yyn);   tmprand=randn(nrp,2);   tmprand=tmprand/max(abs(tmprand(:)))/2;   xxrand=zeros(nrp,nxgrid*nygrid);   yyrand=xxrand;   np=1;   for Nx=1:nxgrid       for Ny=1:nygrid          xxrand(:,np)=xxn(Ny,Nx)+tmprand(:,1);          yyrand(:,np)=yyn(Ny,Nx)+tmprand(:,2);          np=np+1;       end   end   Ind=inpolygon(xxn(:),yyn(:),xx(:),yy(:));   tmpind=1:length(xxn(:));   [jj,ii]=ind2sub(size(xxn),tmpind(Ind==1));   Ind2=sub2ind(size(xxn),jj(:)+1,ii(:));   Ind=sub2ind(size(xxn),jj(:),ii(:));   xxrand(:,Ind2)=xxrand(:,Ind);   yyrand(:,Ind2)=yyrand(:,Ind);      [xxnew,yynew]=GetRandom(xx(:),yy(:),5);   hp0=plot(xxnew,yynew,'g.');set(hp0,'linestyle','none','markersize',1);   %plot(xxn(:),yyn(:),'.b');   hp=plot(xxrand,yyrand,'.g');set(hp,'linestyle','none','markersize',1); end figurenicer; axis equal; axis tight; function [xxnew,yynew]=GetRandom(xx,yy,nrp)  np=length(xx);  if (np>360)     iii=linspace(1,np,360);     iii=fix(iii);     xx=xx(iii); yy=yy(iii);     np=length(xx);  end  tmprand=randn(nrp,2);  tmprand=tmprand/max(abs(tmprand(:)))*8;  xxnew=zeros(nrp,length(xx));  xx=reshape(xx,1,[]);  yy=reshape(yy,1,[]);  xxdif=diff(xx);xxdif=[xxdif(1) xxdif];  yydif=diff(yy);yydif=[yydif(1) yydif];  for N=2:length(xx)      xxnew(:,N)=0.5*(xx(N-1)+xx(N))+tmprand(:,1)*xxdif(N);      yynew(:,N)=0.5*(yy(N-1)+yy(N))+tmprand(:,2)*yydif(N);  end xxnew(:,1)=xxnew(:,2); yynew(:,1)=yynew(:,2);

Fortran Code dealing with longitude

! Copyright by http://scriptdemo.blogspot.com MODULE  mod_longcheck   USE mod_precision   IMPLICIT NONE CONTAINS   FUNCTION Check180(mylon)    ! check whether it is close to the International Date Line (IDL)    logical                    :: Check180    real(kind=rprec)           :: mylon    if ( abs(abs(mylon)-180.0) < 15.0) then    ! here the threshold value is arbitrary       Check180=.TRUE.    else       Check180=.FALSE.    endif   END FUNCTION Check180   FUNCTION CheckZero(mylon)    ! check if whether it is close to the Primary Line    logical                    :: CheckZero    real(kind=rprec)           :: mylon    if ( abs(mylon) < 5.0) then    ! here the threshold value is arbitrary       CheckZero=.TRUE.    else       if (abs(abs(mylon)-360.0)< 5.) then          CheckZero=.TRUE.       else          CheckZero=.FALSE.       endif    endif   END FUNCTION CheckZero   FUNCTION Back180(mylon)   ! convert a longitude into a range of [-180 180]    real(kind=rprec)   :: mylon    real(kind=rprec)   :: Back180    Back180=mylon    if (Back180<0.0) then       do while (Back180 < -180.0)          Back180=Back180+360.0       enddo    else      do while (Back180>180.0)          Back180=Back180-360.0      enddo    endif    return   END FUNCTION Back180   FUNCTION Back360(mylon)   ! convert a longitude into a range of [0 360]    real(kind=rprec)   :: mylon    real(kind=rprec)   :: Back360       Back360=mylon    if (Back360<0.0) then       do while (Back360 < 0.0)           Back360=Back360+360.0       enddo    else       do while (Back360>360.0)         Back360=Back360-360.0       enddo    endif    return   END FUNCTION Back360   SUBROUTINE ll2xy(mylon,mylat,myx,myy)    ! convert given long/latitude into x/y in stereographic projection    real(kind=rprec)   :: mylon,mylat    real(kind=rprec)   :: myx,myy    ! local variables    real(kind=rprec)               :: mypi,deg2r,myphi,mylam    real(kind=rprec)               :: rho,Re,phi0,lam0    real(kind=rprec)               :: a,b,k,f,e,e2,e4,e6,t       Re=6371000.0          ! the earth radius    mypi=acos(-1.0)    deg2r=mypi/180.0    myphi=mylat*deg2r    mylam=mylon*deg2r    phi0=0.    lam0=0.       if (mylat>84.0) then      rho=2.0*Re*(sqrt((1.0-sin(myphi))/(1.0+sin(myphi))))      myx=rho*sin(mylam-lam0)      myy=-rho*cos(mylam-lam0)      myx=myx+2000000.0      myy=myy+2000000.0    elseif (mylat<-84.0) then      ! south-hemisphere stereographic projection      myphi=-myphi      mylam=-mylam      lam0=-lam0           rho=2.0*Re*(sqrt((1.0-sin(myphi))/(1.0+sin(myphi))))      myx=rho*sin(mylam-lam0)      myy=-rho*cos(mylam-lam0)      myx=-myx; myy=-myy      myx=myx+2000000.0      myy=myy+2000000.0    else       stop "NOT DEFINED YET, maybe just not necessary"   endif   END SUBROUTINE ll2xy   SUBROUTINE xy2ll(myx,myy,mylon,mylat)    ! convert given x/y in the stereographic projection into long/latitude    real(kind=rprec)    :: myx,myy    real(kind=rprec)   :: mylon,mylat    ! local variables    real(kind=rprec)               :: mypi,deg2r,myphi,mylam,lat0    real(kind=rprec)               :: xx,yy    real(kind=rprec)               :: rho,Re,phi0,lam0    real(kind=rprec)               :: a,b,k,f,e,e2,e4,e6,t    mypi=acos(1.0)    deg2r=mypi/180.0    Re=6371000.0       lam0=0.0    phi0=0.0    lat0=90.0    if (lat0>84.0) then      xx=myx-2000000.0      yy=myy-2000000.0      rho = sqrt (xx*xx + yy*yy)        myphi=mypi*0.5-2*atan(0.5*rho/Re)      mylam=lam0+atan2(xx,-yy)    elseif (lat0<-84.0) then      stop 'Should not see this msg'      xx=-(myx-2000000.0)      yy=-(myy-2000000.0)      rho=sqrt(xx*xx+yy*yy)      myphi=0.5*mypi-2*atan(0.5*rho/Re)      myphi=-myphi      mylam=-(-lam0+atan2(xx,-yy))    else      stop 'Should not see this msg'    endif      END SUBROUTINE xy2ll END MODULE mod_longcheck

Pack netcdf file

#!/bin/bash # A simple usage of ncpdq from nco (http://nco.sourceforge.net) # Please check more details from the nco website. #   Usage:  packnc.sh myncfile(s) #   NOTE: There will be a loss of precision in type conversion #         (converted to short by default) # Copyright by http://scriptdemo.blogspot.com/   IsNCPDQ=`which ncpdq` if [ ${#IsNCPDQ} -eq 0 ]; then    echo "ncpdq can not be found in the path..."    echo "Please double check your NetCDF Operator (NCO) Path"    exit fi if [ $# -eq 0 ]; then    sed -n '4p' packnc.sh    exit else    Nfiles=$*    for ncfile in ${Nfiles}    do       [ -f ${ncfile} ] && ncpdq -P all_xst ${ncfile}  tmpout_${ncfile} && mv tmpout_${ncfile} ${ncfile}    done fi

Arrays in Bash

#!/bin/bash # # Usage: #       FileNameMon.sh nmon # Copyright by http://scriptdemo.blogspot.com if [ $# -ne 1 ]; then    sed -n '3,4p' FileNameMon.sh    exit fi case $1 in  1)    fnarray[0]="m01d05"    fnarray[1]="m01d10"    fnarray[2]="m01d15"    fnarray[3]="m01d20"    fnarray[4]="m01d25"    fnarray[5]="m01d30"    ;;  2)    fnarray[0]="m02d04"    fnarray[1]="m02d09"    fnarray[2]="m02d14"    fnarray[3]="m02d19"    fnarray[4]="m02d24"    fnarray[5]="m03d01"    ;;  3)    fnarray[0]="m03d06"    fnarray[1]="m03d11"    fnarray[2]="m03d16"    fnarray[3]="m03d21"    fnarray[4]="m03d26"    fnarray[5]="m03d31"    ;;  4)    fnarray[0]="m04d05"    fnarray[1]="m04d10"    fnarray[2]="m04d15"    fnarray[3]="m04d20"    fnarray[4]="m04d25"    fnarray[5]="m04d30"    ;;  5)    fnarray[0]="m05d05"    fnarray[1]="m05d10"    fnarray[2]="m05d15"    fnarray[3]="m05d20"    fnarray[4]="m05d25"    fnarray[5]="m05d30"    ;;  6)    fnarray[0]="m06d04"    fnarray[1]="m06d09"    fnarray[2]="m06d14"    fnarray[3]="m06d19"    fnarray[4]="m06d24"    fnarray[5]="m06d29"    ;;  7)    fnarray[0]="m07d04"    fnarray[1]="m07d09"    fnarray[2]="m07d14"    fnarray[3]="m07d19"    fnarray[4]="m07d24"    fnarray[5]="m07d29"    ;;  8)    fnarray[0]="m08d03"    fnarray[1]="m08d08"    fnarray[2]="m08d13"    fnarray[3]="m08d18"    fnarray[4]="m08d23"    fnarray[5]="m08d28"    fnarray[6]="m09d02"    ;;  9)    fnarray[0]="m09d07"    fnarray[1]="m09d12"    fnarray[2]="m09d17"    fnarray[3]="m09d22"    fnarray[4]="m09d27"    fnarray[5]="m10d02"    ;;  10)    fnarray[0]="m10d07"    fnarray[1]="m10d12"    fnarray[2]="m10d17"    fnarray[3]="m10d22"    fnarray[4]="m10d27"    fnarray[5]="m11d01"    ;;  11)    fnarray[0]="m11d06"    fnarray[1]="m11d11"    fnarray[2]="m11d16"    fnarray[3]="m11d21"    fnarray[4]="m11d26"    fnarray[5]="m12d01"    ;;  12)    fnarray[0]="m12d06"    fnarray[1]="m12d11"    fnarray[2]="m12d16"    fnarray[3]="m12d21"    fnarray[4]="m12d26"    fnarray[5]="m12d31"    ;;  *)    echo "Undefined month: $1"    exit    ;; esac echo ${fnarray[*]}

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mmddstr=(`FileNameMon.sh $month`) # will return an array with the month-day strings.
To get the array size, rather than the length of an array element, either ${#mmddstr[*]} or ${#mmddstr[@]} works well. One should notice that ${#mmddstr} shows something different but the max length of all the array elements.