如何将数据写入TXT文件中的特定位置？

Question

我想更改文本文件的一部分。文件内容如下：

PLANE
CV = 1.4, PRINT = 1
Ks = 3.17, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
PLANE

我想用随机数替换 ks=3.17 部分。更具体地说，文本文件是另一个可执行文件的输入，我想修改Ks值，运行可执行文件，再次修改Ks值，等等。

Answer 1

可能有更好的方法可以做到这一点，但这是有效的。它写入一个新的输出文件，将 Ks 值更改为 9.99。

Program modify_value

implicit none

character(len=100) :: row
integer :: j
real :: Ks

Ks = 9.99

open(unit=1,file='data.txt',status='old')
open(unit=2,file='data_modified.txt',status='unknown')

do j=1,4
  read(1,'(a)') row
  if (j==3) then
    write(2,'(a,F5.2,a)') row(1:4), Ks, trim(row(10:))
  else
    write(2,'(a)') trim(row)
  end if
end do

close(1)
close(2)

End Program

Answer 2

您有充分的理由使用 Fortran 来完成这项任务吗？您在上一段中描述的任务可以使用其他语言轻松完成。例如，如果您编写如下所示的 python 脚本，

import os, random

# repeat 10 times
for i in range(10):

    # generate random Ks with Normal distribution, mean=3.17, stdev=1
    ks = random.normalvariate(3.17,1)

    # write input file
    with open('inp.txt','w') as f:

        f.write( 
"""PLANE
CV = 1.4, PRINT = 1
Ks = %4.2f, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
PLANE""" % ks )


    # run the program
    os.system("a.exe")

给定这样的示例 fortran 程序，

program test
  character(len=80) :: line
  open(10,file='inp.txt',status='old')
  do i=1,4
  read(10,'(a)') line
  write(*,*) trim(line)
  enddo
end program

您将得到

$ python test.py
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 1.21, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 3.08, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 4.55, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 4.10, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 2.24, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 4.62, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 2.76, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 2.69, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 4.58, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE
 PLANE
 CV = 1.4, PRINT = 1
 Ks = 3.32, G = 120.67, DIST = 0.34, POR = 0.456, ROCK = 0.3
 PLANE