Read data with name and value from txt in fortran separated by commas

[Dvocvet]

Hi everybody

I need to read some data from txt file in format for example like these:

a=150,b=300,c=500

Then I will use that data for further calculating. For example:

x=a+b+c

Is that possible in Fortran? Is there some command or format for READ command?
Please help!

 

[FJacq]

The general way to do that consists in :

- reading the entire line as a text,

- looking for the character "," to tokenize that text,

- looking for the character = to separate the name and the value in each token

- reading the value in each token

But it exists also easier possibilities if you accept to modify a little bit the form of the data like. For instance, the use of a namelist :

program t59
  implicit none
  double precision :: a,b,c,y
  namelist/list/a,b,c
  read(*,list)
  y=a+b+c
  write(*,*) y
end program

The data become :

&list
a=150,b=300,c=500
/

Here is the result :

[lcoul@localhost test]$ ifort t59.f90
[lcoul@localhost test]$ ./a.out < d
   950.000000000000

Notice that a namelist is very flexible :

- it is possible to initialize the variables in the source file before reading the namelist and to provide, in the data, only few changes.

- it is possible to include in a namelist many kinds of variables like arrays, derived type and even allocatable variables.

- an array in a namelist may be initialized globally or element by element



François Jacq

 

[mikrom]

Look at some older threads how to parse config file:

http://www.tek-tips.com/viewthread.cfm?qid=1662044

http://www.tek-tips.com/viewthread.cfm?qid=1602458

 

[Dvocvet]

Thanks people.

I solved problem on the next way:

program prog

implicit none
double precision::kapa,r2,T2,a2

open (1,file='list.txt')
read (1,*) (kapa,r2,T2)


a2=sqrt(kapa*r2*T2)

print *, "a2=",a2
end program prog

Where input data in list.txt look like these:

1.4,280,333

So, input data are without name of data and '='.