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

 ; 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, character, or string.

 ; String fields cannot be written to a netCDF file. They have to

 ; be read in as character arrays and written out that way.

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

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

 ; 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, character, 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. For string, int, float, or double arrays,

 ; we don't have to do anything special. For character arrays,

 ; however, we do.

 ;

   if(return_type.ne."character") then

     return_array = new(nrows,return_type)

   else

 ;

 ; We don't know what the biggest character array is at this point, so

 ; make it bigger than necessary, and then resize later as necessary.

 ;

     tmp_return_array = new((/nrows,dimsizes(cstrings(0,:))/),"character")

     max_len = 0     ; Use to keep track of max lengths of strings.

   end if

   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

     if(return_type.eq."character") then

       if( (iend-ibeg+1) .gt. max_len) then

         max_len = iend-ibeg+1

       end if

       tmp_return_array(i,0:iend-ibeg) = cstrings(i,ibeg:iend)

     end if

   end do

   if(return_type.eq."character") then

     return_array = new((/nrows,max_len/),"character")

     return_array = tmp_return_array(:,0:max_len-1)

   end if

   return(return_array)

 end

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

 ; This function reads in string fields only to get the maximum string

 ; length.

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

 function get_maxlen(strings,ifield,indices)

 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

 ;

 ; We don't know what the biggest character array is at this point, so

 ; make it bigger than necessary, and then resize later as necessary.

 ;

   tmp_return_array = new((/nrows,dimsizes(cstrings(0,:))/),"character")

   max_len = 0     ; Use to keep track of max lengths of strings.

   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

     if( (iend-ibeg+1) .gt. max_len) then

       max_len = iend-ibeg+1

     end if

   end do

   return(max_len)

 end

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

 ; Main code.

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

 begin

 ;

 ; Set up defaults here.  We are hard-coding the field types here.

 ; You can set up this script to try to determine the field types 

 ; automatically, but this is a bit tedious. Maybe later.

 ;

   filename  = "data.933"                ; ASCII" file to read.

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

   nfields   = 45                        ; # 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_strlens    = new(nfields,integer)   ; var to hold strlens, just in case.

   var_types      = "integer"       ; Most are ints.

   var_types(5:7) = "character"     ; 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 names to file. If there are no character variables,

 ; then there's only one dimension name ("nvalues").

 ;

 ; Otherwise, we need to write a dimension name for every character

 ; variable, which will indicate the maximum string length for that

 ; variable.

 ;

   indc = ind(var_types.eq."character")

   if(.not.any(ismissing(indc))) then

 ;

 ; We have to treat the character arrays special here. We need to

 ; know their sizes so we can write the maximum size of each char

 ; array to the netCDF file as a dimension name. This means we

 ; need to read in the character variables once to get the string

 ; lengths, then we'll read them again later to get the actual values.

 ;

     do i=0,dimsizes(indc)-1

       var_strlens(indc(i)) = get_maxlen(data,indc(i)+1,dindices)

     end do

     ndims    = dimsizes(indc) + 1

     dimNames = new(ndims,string)

     dimSizes = new(ndims,integer)

     dimUnlim = new(ndims,logical)

     dimUnlim            = False

     dimUnlim(0)         = True

     dimNames(0)         = "nvalues"

     dimNames(1:ndims-1) = var_names(indc) + "_StrLen"

     dimSizes(0)         = -1

     dimSizes(1:ndims-1) = var_strlens(indc)

     filedimdef(f,dimNames,dimSizes,dimUnlim)

   else

 ;

 ; No character variables, so just write the one dimension name.

 ;

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

   end if

 ;

 ; Define each variable on the file.

 ;

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

 ;

   do i=0,nfields-1

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

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

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

       else

         filevardef(f, var_names(i), var_types(i),  \

                    (/"nvalues",var_names(i)+"_StrLen"/))

       end if

     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.

 ;

 ; Note: you can't write strings to a netCDF file, so these have

 ; to be written out as character arrays.

 ;

     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) + ".")

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

       print("min/max = " + min(tmp_data) + "/" + max(tmp_data))

     end if

     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 do

 end