open file text with special format

[Khaled Tahoon]

Hello, I' m a new with idl programming. 

attach includes a file of regional climate model. 

Does anyone help me to open the file and read the data of Lon., Lat., and Ps for contour plot using IDL under windows operating system.

Thanks 

[markus.sc...@gmail.com]

Hi Khaled, 

try the code below. Please loom up the documentation of the function and methods you don't know.

I hope this helps, Markus

function extract_value, lines, start, ends
  val = strsplit(lines[start:ends],' ,;',/extract)
  val = val.map('float')
  return, val.reduce(lambda('x,y:[x,y]'))
end

filename='Downloads/ps_200605.txt'
print, file_test(filename,/read)
n_lines =file_lines(filename)
lines=strarr(n_lines)
openr, lun, filename,/get_lun
readf, lun, lines
free_lun, lun

posi = lonarr(3)
foreach  var,['xlon','xlat','ps'],i do posi[i] = $
    where(stregex(lines,' *'+var+' *= *',/boolean))
semicolon = where(stregex(lines,'.* *; *',/boolean))

xlon = extract_value(lines, posi[-3]+1, semicolon[-3])
xlat = extract_value(lines, posi[-2]+1, semicolon[-2])
ps   = extract_value(lines, posi[-1]+1, semicolon[-1])

c=contour(ps,xlon,xlat)

[Khaled Tahoon]

Hi Markus,

Thanks a lot for your kindly reply.
unfortunately,  the foreach statement is not run under my IDL version.

I modified your code as follows:

filename='downloads\ps_200605.txt'

n_lines =file_lines(filename)
lines=strarr(n_lines)
openr, lun, filename,/get_lun
readf, lun, lines
free_lun, lun

var=['xlon','xlat','ps']
posi=lonarr(3)
for i=0, n_elements(Var) - 1 do begin
posi[i] = where(stregex(lines,' *'+var[i]+' *= *',/boolean))

semicolon = where(stregex(lines,'.* *; *',/boolean))

endfor
when I run your code, I get that POSI is Out of range subscript encountered

and then the following statement will be incorrect. 

xlon = extract_value(lines, posi[-3]+1, semicolon[-3])

could you please explain for me what do you means -3 in both posi[-3] and semicolon[-3].

I would like to read the ps parameter as function in Jx, Iy. 

So, PS become a 2-D array or matrix with rank of Jx * Iy 

regards 

Khaled

please, attach file is the model output. 

In addition, for example, in this file one read the 

dimensions:

time = UNLIMITED ; // (1 currently)
bnds = 2 ;
jx = 237 ;

iy = 197 

variables:
double time(time) ;
time:standard_name = "time" ;
time:long_name = "time" ;
time:bounds = "time_bnds" ;
time:units = "hours since 1949-12-01 00:00:00 UTC" ;
time:calendar = "gregorian" ;
time:axis = "T" ;

how one can read each parameter.   

[Khaled Tahoon]

Hello Markus,

I modified your code as follows:-  

;==================================
file='downloads\ps_200605.txt'
n_lines =file_lines(file)
lines=strarr(n_lines)
openr, lun, file,/get_lun

readf, lun, lines
free_lun, lun

var_k=['xlon','xlat','Ps']
posi=lonarr(3)
for i=0L, n_elements(Var_k) - 1L do begin
semicolon = where(stregex(lines,'.* *; *',/boolean))  ; this command is correct
posi[i] = where(stregex(lines,' *'+var_k[i]+' *= *',/boolean))    
endfor

n_semicolon=n_elements(semicolon)
Inv_Ind_semicolom= (n_semicolon-1)-Indgen(n_semicolon)

print, posi[0]+1, semicolon[Inv_Ind_semicolom[2]]
print, posi[1]+1, semicolon[Inv_Ind_semicolom[1]]
print, posi[2]+1, semicolon[Inv_Ind_semicolom[0]]
xlon = extract_value(lines, posi[0]+1, semicolon[Inv_Ind_semicolom[2]])
xlat = extract_value(lines, posi[1]+1,  semicolon[Inv_Ind_semicolom[1]])
ps   = extract_value(lines, posi[2]+1,  semicolon[Inv_Ind_semicolom[0]])
print, xlon.val
print, xlat.val
print, ps.val
end

function extract_value, lines, start, ends
  val = strsplit(lines[start:ends],' ,;',/extract)
  val = val.map('float')

  dims = Image_Dimensions(Val, XSize=XSize, YSize=YSize, TrueIndex=trueindex)

  return, val.reduce(lambda('x,y:[x,y]'))
end

;====================

I still have some errors in my code such as. 

STRTOK: Expression must be a scalar or 1 element array in this context: STRINGIN. related to Xlon, xlat, and Ps

what means  val.map('float') in the subroutine.

In addition, I need an alternative statements of reduce(lambda('x,y:[x,y]')).

Best regards

Khaled