Fortran [FORTRAN] Character Substring Extracting

[Nicolaus]

How would I go about extracting the 3 substrings delimited by the slashes in the date?
The date is a string in the format "d/m/y"
This subprogram checks if there are at least 2 slashes for correct format, and then, if the format is correct, the program would then extract the day, month, and year substrings delimited by the slashes, which is where I'm stuck.

subroutine checkFormat (date, day, month, year, yes)
character*(*) date, day, month, year
logical yes
integer i, count

do while (count .ge. 0 .and. count .lt. 2)
do i = 1, len(date)
if (date(i:i) .eq. "/") then
count = count + 1
end if
end do
if (count .lt. 2) then
yes = .false.
return
end if
end do

return
end

 

[AlephZero]

There are two bugs in your code: you forgot to initialize the variables "count" and "yes" to something.

When you have found the first "/", variable "i" is the position of the "/", so you know the "day" part of the string is date{1:i-1).

You can get the "month" and "year" parts in a similar way. You probably want to remember where the first "/" was, while you are looking for the second one.

 

[Mark44]

How would I go about extracting the 3 substrings delimited by the slashes in the date?
The date is a string in the format "d/m/y"
This subprogram checks if there are at least 2 slashes for correct format, and then, if the format is correct, the program would then extract the day, month, and year substrings delimited by the slashes, which is where I'm stuck.

subroutine checkFormat (date, day, month, year, yes)
character*(*) date, day, month, year
logical yes
integer i, count

do while (count .ge. 0 .and. count .lt. 2)
do i = 1, len(date)
if (date(i:i) .eq. "/") then
count = count + 1
end if
end do
if (count .lt. 2) then
yes = .false.
return
end if
end do

return
end

First off, having a logical variable named yes is nonsensical. A better name might be isValid.

When you determine that date has two slashes in it, keep track of their positions. For example, if date is "21/3/13", the first slash is at index 3 and the second slash is at index 4. date(1:2) would hold the day, date(4:4) would hold the month, and date(6:7) would hold the year.

 

[gsal]

Fortran has an intrinsic string function INDEX that returns the index of a character in a string, it can work forwards (from left to right) and backwards (from right to left)

You can find the two indices for the '/ ' character, if they are equal, you do not have two slashes
if they are different, say, k and m, then,

day is in date(:k-1)
month is in date(k+1:m-1)
year is in date(m+1:)

 

[Nicolaus]

Thanks; solved it!

 

[Lyndz]

Convert text file to csv formatted file

Hi all,
I have station data in a text file and I want to read it using grads and output as a csv file.
The problem is the dates are separated by a backslash...
here's a sample format:

The text file contains the following data.

yy/mm/dd/hh pressure rain TEMPERATURE wind speed
2012/08/06/00 10000 2.5 300 45
...
...
...
...


I want to oputput this in a csv format such that the the years, months, days, and hours are in separated in columns...
like:

yy mm dd hh rain temperature wind speed

 

[SteamKing]

As long as the structure of the data is the same throughout the text file, then read the data with the proper FORMAT statement:

READ (IUNIT,1010) IYEAR,MONTH,IDAY,IHOUR,PRESS,RAIN,TEMP,WSPEED
1010 FORMAT (I4,1x,I2,1x,I2,1x,I2,1x,I5,F3.1,I4,I3)

This is the basic idea. It will need modification to fit into your program. The idea here is, if the '/' are always in the same column, you can skip reading them and you don't have to make your program parse the data file to determine what is data and what is a separator.