;----------------------------------------------------------------------

 ; This example reads an ASCII file that is formatted a specific way, and

 ; writes out the results to a netCDF file.

 ;

 ; The first line in the ASCII file must be a header, with each field

 ; separated by a single character delimiter (like a ","). The rest of

 ; the file must be such that each row contains all fields, each

 ; separated by the designated delimiter.

 ;

 ; The fields can be integer, float, double, or string.

 ;----------------------------------------------------------------------

 ;----------------------------------------------------------------------

 ; This function returns the index locations of the given delimiter

 ; in a row or several rows of strings.

 ;----------------------------------------------------------------------

 function delim_indices(strings,nfields,delimiter)

 local cstrings, cdelim

 begin

   nrows = dimsizes(strings)

 ;

 ; Handle special case if we only have one string. Make sure it

 ; is put into a 2D array.

 ;

   if(nrows.eq.1) then

     cstrings = new((/1,strlen(strings)+1/),character)

   end if

   cstrings = stringtochar(strings)        ; Convert to characters.

   cdelim   = stringtochar(delimiter)      ; Convert delimiter to character.

 ;

 ; Som error checking here. Make sure delimiter is one character.

 ;

   nc   = dimsizes(cdelim)

   rank = dimsizes(nc)

   if(rank.ne.1.or.(rank.eq.1.and.nc.ne.2)) then

     print("delim_indices: fatal: the delimiter you've selected")

     print("must be a single character. Can't continue.")

     exit

   end if

 ;

 ; Create array to hold indices of delimiter locations, and then loop

 ; through each row and find all the delimiters. Make sure each row has

 ; the correct number of delimiters.

 ;

   ndelims  = nfields-1

   cindices = new((/nrows,ndelims/),integer)

   do i = 0, nrows-1

     ii = ind(cstrings(i,:).eq.cdelim(0))

 ;

 ; Make sure there were delimiters on this row. If not, we just quit.

 ; This could probably be modified to do this more gracefully.

 ;

     if(any(ismissing(ii))) then

       print("delim_indices: fatal: I didn't find any delimiters")

       print("('" + delimiter + "') on row " + i + ". Can't continue.")

       exit

     end if

     if(dimsizes(ii).ne.ndelims) then

       print("delim_indices: fatal: I expected to find " + ndelims)

       print("delimiters on row " + i + ". Instead, I found " + dimsizes(ii) + ".")

       print("Can't continue.")

       exit

     end if

     cindices(i,:) = ii

     delete(ii)            ; For next time through loop

   end do

   return(cindices)

 end

 ;----------------------------------------------------------------------

 ; This function reads in a particular field from a string array,

 ; given the field number to read (fields start at 1 and go to nfield),

 ; and the indices of the delimiters.

 ;

 ; It returns either an integer, float, double, or a string,

 ; depending on the input flag "return_type".

 ;----------------------------------------------------------------------

 function read_field(strings,ifield,indices,return_type)

 local nstring, cstrings, nf, tmp_str

 begin

   nrows = dimsizes(strings)

 ;

 ; Handle special case if we only have one string. Make sure it

 ; is put into a 2D array.

 ;

   if(nrows.eq.1) then

     cstrings = new((/1,strlen(strings)+1/),character)

   end if

   cstrings = stringtochar(strings)

   nf       = dimsizes(indices(0,:))+1     ; indices is nrows x (nfields-1)

 ;

 ; Error checking. Make sure user has entered a valid field.

 ;

   if(ifield.le.0.or.ifield.gt.nf) then

     print("read_field: fatal: you've selected a field that is")

     print("out-of-range of the number of fields that you have (" + nf + ").")

     exit

   end if

 ;

 ; Set up array to return.

 ;

   return_array = new(nrows,return_type)

   do i = 0,nrows-1

 ;

 ; Special case of first field in row.

 ;

     if(ifield.eq.1) then

       ibeg = 0

       iend = indices(i,ifield-1)-1

     else

 ;

 ; Special case of first field in row.

 ;

       if(ifield.eq.nf) then

         ibeg = indices(i,ifield-2)+1

         iend = dimsizes(cstrings(i,:))-1

 ;

 ; Any field between first and last field.

 ;

       else

         ibeg = indices(i,ifield-2)+1

         iend = indices(i,ifield-1)-1

       end if  

     end if

 ;

 ; Here's the code that pulls off the correct string, and converts it

 ; to float if desired.

 ;

     if(return_type.eq."integer") then

       return_array(i) = stringtointeger(chartostring(cstrings(i,ibeg:iend)))

     end if

     if(return_type.eq."float") then

       return_array(i) = stringtofloat(chartostring(cstrings(i,ibeg:iend)))

     end if

     if(return_type.eq."double") then

       return_array(i) = stringtodouble(chartostring(cstrings(i,ibeg:iend)))

     end if

     if(return_type.eq."string") then

       return_array(i) = chartostring(cstrings(i,ibeg:iend))

     end if

   end do

   return(return_array)

 end

 ;----------------------------------------------------------------------

 ; Main code.

 ;----------------------------------------------------------------------

 begin

 ;

 ; Set up defaults here.  We have to hard-code the field types,

 ; because we can't really tell otherwise.

   filename  = "data.81"                 ; ASCII" file to read.

   cdf_file  = filename + ".nc"          ; netCDF file to write.

   nfields   = 22                        ; # of fields

   delimiter = ","                       ; field delimiter

 ;

 ; In this case, fields #6-#8 are strings, fields #2, #3, and #11

 ; are float, and the rest of the fields are integers.

 ;

   var_types      = new(nfields,string)

   var_types      = "integer"    ; Most are ints.

   var_types(5:7) = "string"     ; corresponds to fields 6-8

   var_types(1:2) = "float"

   var_types(10)  = "float"

   if(isfilepresent(cdf_file))

     print("Warning: '" + cdf_file + "' exists. Will remove it.")

     system("/bin/rm " + cdf_file)

   end if

 ;

 ; Read in data as strings. This will create a string array that has the

 ; same number of strings as there are rows in the file. We will then need

 ; to parse each string later.

 ;

   read_data = asciiread(filename,-1,"string")

   header    = read_data(0)        ; Header. Use for variable names.

   data      = read_data(1:)       ; Get rid of first line which is a header.

   nrows     = dimsizes(data)      ; Number of rows.

 ;

 ; Read in locations of delimiters in each string row.

 ;

   hindices = delim_indices(header,nfields,delimiter)   ; header row

   dindices = delim_indices(data,nfields,delimiter)     ; rest of file

 ;

 ; Read in the field names which will become variable names on

 ; the netCDF file.

 ;

   var_names = new(nfields,string)

   do i=0,nfields-1

     var_names(i) = read_field(header,i+1,hindices,"string")

   end do

 ;

 ; Write out this netCDF file efficiently so it will be faster.

 ; Try to predefine everything before you write to it.

 ; 

   f = addfile(cdf_file,"c")

   setfileoption(f,"DefineMode",True)       ; Enter predefine phase.

 ;

 ; Write global attributes to file. It's okay to do this before 

 ; predefining the file's variables. We are still in "define" mode.

 ;

   fAtt               = True

   fAtt@description   = "Data read in from '" + filename + "' ASCII file."

   fAtt@creation_date = systemfunc ("date")        

   fileattdef( f, fAtt )        

 ;

 ; Write dimension name. There's only one here.

 ;

   filedimdef(f,"nvalues",-1,True)

 ;

 ; Define each variable on the file, giving it the dimension name

 ; we just created above.

 ;

 ; Don't deal with variables that are of type string.

 ;

   do i=0,nfields-1

     if(var_types(i).ne."string") then

       filevardef(f, var_names(i), var_types(i), "nvalues")

     end if

   end do

 ;

 ; Loop through each field, read the values for that field, print 

 ; information about the variable, and then write it to the netCDF

 ; file.

 ;

   do i=0,nfields-1

     ifield = i+1           ; Fields start at #1, not #0.

 ;

 ; You can't write strings to a netCDF file, so skip the string fields.

 ;

     if(var_types(i).ne."string") then

       tmp_data = read_field(data,ifield,dindices,var_types(i))

 ;

 ; Print some info about the variable.

 ;

       print("")

       print("Writing variable " + var_names(i) + " (field #" + ifield + ").")

       print("Type is " + var_types(i) + ", min/max = " + min(tmp_data) + \

             "/" + max(tmp_data))

       if(any(ismissing(tmp_data))) then

         print("This variable does contain missing values.")

       else

         print("This variable doesn't contain missing values.")

       end if

       f->$var_names(i)$ = tmp_data       ; Write to netCDF file.

       delete(tmp_data)                   ; Delete for next round.

     end if

   end do

 end