How to make a program read one file and write the changed data to another in Python?

Question

Python

There is a program that edits a file, how can I make it not edit the same file that I selected, but only read it and write the changes to another?

Here is the code

def change():
    file_name = fd.askopenfilename()
    f = open(file_name,'r')
    lines = f.read()
    lines = lines.replace('Путей в парке', '')
    lines = lines.replace(';--------------', '')
    while "  " in lines:
        lines = lines.replace("  ", " ")

    level1 = None
    level2 = None
    for line in lines.split('\n'):
        result1 = re.match('^@\s+(\d+)\s+(.*)$', line)
        if result1:
            level1 = f'{result1.group(1)};{result1.group(2)}'
            continue
        if re.match('#', line):
            level2 = line
            continue
        if level1 and level2:
            if level1 and level2 and line:
                line = line.replace(' ', '; ')
                print(f'{level1};{level2}{line}')
                f.close()
                save_changes = open(file_name, 'w')
                save_changes.writelines(lines)
                save_changes.close()

Answer 1

Something like this

with open('somefile', 'w+') as write_file:
     with open('someotherfile', 'r') as read_file:
          data = read_file.read()
          outdata = f(data)
          write_file.write(outdata)

Answer 2

# читаем исходник
text = open('file1.txt', 'r').read()
# изменяем
text += 'test'
# записываем во второй
f = open('file2.txt', 'w')
f.write(text)
f.close()

In your case

def change():
    file_name = fd.askopenfilename()
    file_name1 = 'второй файл'
    f = open(file_name,'r')
    lines = f.read()
    lines = lines.replace('Путей в парке', '')
    lines = lines.replace(';--------------', '')
    while "  " in lines:
        lines = lines.replace("  ", " ")

    level1 = None
    level2 = None
    for line in lines.split('\n'):
        result1 = re.match('^@\s+(\d+)\s+(.*)$', line)
        if result1:
            level1 = f'{result1.group(1)};{result1.group(2)}'
            continue
        if re.match('#', line):
            level2 = line
            continue
        if level1 and level2:
            if level1 and level2 and line:
                line = line.replace(' ', '; ')
                print(f'{level1};{level2}{line}')
                f.close()
                save_changes = open(file_name1, 'w')
                save_changes.writelines(lines)
                save_changes.close()