CODEWITHSUNDEEP
stringfilefortranformat
Bruno Fonseca
Bruno Fonseca

Reputation: 93

Is there a way to compare the format in which a line of a text file was written in Fortran?

I'm developing a Fortran program that must obtain some data from a text file and generate another text file using specific data from the first one. The input file have many lines written in several specific formats which I know of. Although I know the formats, the lines in this file are generated in a "random way".

It would be much easier to generate the output file if I could compare the format in which each line was written, then I would know exactly what data I can get from that line of the input file to use it in the output file.

What I need is something like, for example, knowing that the format of the line read and stored in the LINHA variable is described in the FORMATO variable, do something like:     

IF (FORMATO = '(1X, 15,3F8.1,2 (5A, 1X))') THEN
  READ (LINHA, '(6X, F8.1)') my_variable
END IF

Because there might be another format such as

'(6A, 2F8.1, F8.6,2 (6A))'

in which, if I use the same READ statement, I will read an F8.1 variable in my_variable, however this value is not the correct one.

Upvotes: 0

Views: 239

Answers (4)

Bruno Fonseca
Bruno Fonseca

Reputation: 93

Problem solved using a mixture of some of the suggestions posted. I read each of the lines of the input file in an internal variable (RLINFILE) in the format '(A165)'. After that, I read all the contents of the string that I put in this internal variable in several dummy variables, using the format I knew of the lines from where I wanted to get some information (read all the information of the line in the desired and get IOSTAT = 0 guarantee that this is the correct line), so if the result of the reading is ok (IOSTAT = 0), it is because the line I just read was the correct one for the information I wanted, so I store the contents of some of the dummy variables that represent the values that interest me. In the code, the solution looked something like this:

OPEN(UNIT=LU1,FILE=RlinName,STATUS='OLD')
ilin = 0
formato = '(14X,A,1X,F7.1,1X,F7.1,5X,A,1X,A,1X,A,5X,A,I5,1X,A,I3,3F8.1,A,A,A,1X,A,2(1X,F8.2),1X,A,1X,A)'
DO WHILE (.TRUE.)
  READ(LU1,'(A165)',END=300) RLINFILE
  READ(RLINFILE,formato,IOSTAT=linhaok) dum2_a1,dum2_f1,dum2_f2,dum2_a2,dum2_a3,dum2_a4,dum2_a5,dum2_i1,dum2_a6,dum2_i2,dum2_f3,dum2_f4,dum2_f5,dum2_a7,dum2_a8,dum2_a9,dum2_a10,dum2_f6,dum2_f7,dum2_a11,dum2_a12
  IF(linhaok.EQ.0) THEN
    ilin = ilin+1
    rlin_lshu(ilin) = dum2_a4
    rlin_nbpa(ilin) = dum2_i1
    rlin_ncir(ilin) = dum2_i2
    rlin_ppij(ilin) = dum2_f3
    rlin_pqij(ilin) = dum2_f4
    rlin_tapn(ilin) = dum2_a7
  END IF
END DO
300 CLOSE(UNIT=LU1)

Upvotes: 1

Alfonso Sancho
Alfonso Sancho

Reputation: 136

The best option is to read without format, keeping each line in a character array. Then read the line variable as an internal file with the required format using the variable IOSTAT in order to check if the format is the correct.

INT max_size = 80
CHARACTER(LEN=max_size) :: line
READ(*,*) line
READ(line,'(1X, 15,3F8.1,2 (5A, 1X))',IOSTAT=ios) var1, var2, ...

Upvotes: 1

Scientist
Scientist

Reputation: 1835

The description of the problem you are trying to solve is a bit vague to me, but the simplest solutions that comes to my mind, given the description of the problem, is to modify the original code that generates the input data file, to write the used Fortran READ format before the data line in the input file. This way, you can read the format as a string and use it in the subsequent data IO in your second code.

If you describe the specific task your tryting to accomplish in more details, perhaps more experienced Fortranners could help.

Upvotes: 0

Aristotelis
Aristotelis

Reputation: 141

A (not so elegant) work-around that I can think of is to read the entire line using the advance = no option of read() and parse each character in the line separately. While doing so, you may count white spaces or other specific characters that you know of and then identify the different formats from there. It would be helpful if you could give more specifications of the nature of the task.

Upvotes: 3

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