Open all files in folder python

Question

I have this function that is supposed to open all text files in a folder and remove all the "\\n" in it.

def FormatTXT():

    conhecimentos = os.listdir('U:/AutoCTE/Conhecimentos')

    for x in conhecimentos:
        with open(x, "r+") as f:
            old = f.read()
            text = old.replace("\n", "")
            f.seek(0)
            f.truncate(0)
            f.write(text)
            f.close()

But this function is returning the following error:

FileNotFoundError: [Errno 2] No such file or directory: '20200119-170415-Conhecimento de Transporte.txt'

Happens that this file actually exists in the directory and I can't figure out what I'm missing.

Answer 1

The file paths that you open in x are missing the prefix U:/AutoCTE/Conhecimentos . And since you are in a different directory, those relative paths will not work

def FormatTXT():

    conhecimentos = os.listdir('U:/AutoCTE/Conhecimentos')

    for x in conhecimentos:
        with open('U:/AutoCTE/Conhecimentos/' + x, "r+") as f:
            old = f.read()
            text = old.replace("\n", "")
            f.seek(0)
            f.truncate(0)
            f.write(text)
            f.close()

There are better ways to do this. For example with the os.path module

Answer 2

I think the main problem you have is that you forgive to notice that os.listdir() return the name of the file in a directory not their path, you have to append the file name to the dir path using os.path.join()

There are several way to do this I will pick the 3 I use.

first let write a function that remove parse the file text because you get it right , I would just recommend caution using read() in case of very large file.

def remove_end_lines(file_): 
    """
    remove "\n" from file
    """
    with open(file_, "r+") as f:
        old = f.read()
        text = old.replace("\n", "")
        f.seek(0)
        f.truncate(0)
        f.write(text)

now we have to tackle your main problem file path. -> a choice could be to change the working dir (you should first register the original working dir in order to be able to go back to it)

def FormatTXT(my_dir):

    original_dir = os.getcwd() # register original working dir
    conhecimentos = os.listdir(my_dir) # liste file in the dir
    os.chdir(my_dir)  # change dir

    for file_ in conhecimentos: 
        remove_end_lines(file_)

    os.chdir(original_dir) # go back to original dir

second choice let's use os.path.join()

def FormatTXT(my_dir):

    conhecimentos = os.listdir(my_dir) # liste all files in the dir

    for file_ in conhecimentos: 
        file_path = os.path.join(my_dir, file_)  # create the file path by appening the file name to the directory path
        remove_end_lines(file_path)

In case you have subdirectory and want to perform the same operation you should use os.walk()

def FormatTXT(my_dir):
    for dir_path, dir_name, files_name in os.walk(my_dir):
    # files_name is a list of all file in dir_path,
        if files_name:  # if there is file in the current dir (the list is not empty)

        for file_ in files_names:
            file_path = os.path.join(my_dir, file_)  
            remove_end_lines(file_path)

I hope this help. if you have more question don't hesitate to ask