Reading variables from a file in fortran

Question

I'm working with a fortran program that reads a lot of data from a file and writes it back in a different format.

The code I'm using to read the data is this:

10  read(10,*,err=11,end=20) f,time(i),(a(i,j),j=1,14)
    ... 
    goto 10
11  i=i+1
    goto 10

It works, but only when the input file is correct. But some lines are like this:

"2014-04-28 07:51:18.9",2705,-8.42144,6.623851,0.4654102,20.99942,"NAN","NAN",0,0,0,0,-9.0605,5.8855,0.4135,21.39728

When this happens I lose every value in the line after the NAN. Is there a way to read the other values?

It's possible to read every value as a string and then convert them to doubles? I know very little about fortran and I need to fix it quickly. Rewriting everything in C could take too much time.

Answer 1

Yes, you can read the entire line into a string. Then parse the string and replace the "NAN" with some special numeric value such as a large negative value. The intrinsic functions can help, e.g., index. Then use an "internal read" to read from the string into the numeric variables.

See: Reading comment lines correctly in an input file using Fortran 90, Reading format in Fortran 90 and Prevent FORTRAN from closing when a character is inputed instead of a number

Answer 2

I got it working. Here is the code:

  10  read(10,'(a)',err=16,end=20) linha
      linha=trim(adjustl(linha))
      pos1=1
      n2=0
      DO
      pos2 = INDEX(linha(pos1:), ",")

      IF (pos2 == 0) THEN
      n2 = n2 + 1
      strings(n2) = linha(pos1:)
      EXIT
      END IF
      n2 = n2 + 1
      strings(n2) = linha(pos1:pos1+pos2-2)
      pos1 = pos2+pos1
      END DO

      f=strings(1)
      read(strings(2),*) time(i)

      j=1
  11  read(strings(j+2), *,err=12) a(i,j)
      j=j+1
      IF (j > 14) THEN
      goto 13
      END IF
      goto 11

  12  a(i,j)=9999
      j=j+1
      goto 11

  13  IF (a(i,6)==9999) THEN
      goto 14
      END IF
      pp=1000.
      c1=0.622
      c2=1.-c1
      rv=461.5
      e=0.001*a(i,6)*rv*(a(i,4)+273.15)
      a(i,6)=1000*e*c1/(100*pp-c2*e)    
  14  IF (a(i,5)==9999) THEN
      goto 15
      END IF 
      mimol=a(i,5)/44
      a(i,5)=mimol*83.14*(a(i,4)+273.15)/pp
  15  i=i+1
      n=i-1
      if (i.gt.nmax) goto 20
      goto 10

  16  i=i+1
      goto 10

Thanks for the help.