替换在字符串中具有浮点数并写入新文件Python的变量

Question

My question is about how to open a file, change a variable in a line.

Example:

Modelica.SIunits.Height Hfsc = 3.7 "ground floor";

I need to change the Hfsc = 3.7 to Height_1 = 2 and then save the changes in a new file. It should be something like this:

Modelica.SIunits.Height Height_1 = 2 "ground floor";

path = '/Users/project.mo'

with open(path, 'r') as f:

    for line in f:

        Height_1 = 2 # defined a variable
        float = 3.7 # do I need to define the 3.7 as a float?

        if "parameter Modelica.SIunits.Height Hfsc" in line:
            str2 = "Hfsc" print(line.find(str2))
            print(line.find('=', 37))
            print(line.find('"', 49))
            indices = [0, 44, 55]
            # indices to identify the splitting position of the string
            parts = [line[i:j] for i, j in zip(indices, indices[1:] [None])

            print(parts)

Output:

parameter Modelica.SIunits.Height ', 'Hfsc = 3.7 ', '"ground  floor";\n']

I can split the line, put I can't replace the variable Hfsc = 3.7 with Height_1 = 2 and write a new file.

Answer 1

I suggest that you use regular expressions for the substitution and then write to the file. You could then simultaneously open two files, substitute and write to the new file like so:

import re to_sub = 'parameter Modelica.SIunits.Height Hfsc = 3.7 "ground floor"' replacement = 'parameter Modelica.SIunits.Height Height_1 = 2 "ground floor"' with open(in_path, 'r') as inf, open(out_path, 'w') as outf: for line in inf: subbed_line = re.sub(to_sub, replacement, line) outf.write(subbed_line)

Hope you found this helpful!

Answer 2

If the input is consistent enough, you should be able to simply do this:

path = '/Users/project.mo'
newpath = '/Users/project_new.mo'

with open(path, 'r') as fin, open(newpath, 'w') as fout:
    for line in fin:
        if "parameter Modelica.SIunits.Height Hfsc = 3.7" in line:
            line = line.replace("Hfsc = 3.7", "Height_1 = 2")

        fout.write(line)