Python代码未写入文件

Question

I have several text files in a folder, containing a list of names and adjectives. I have managed to create a script that takes random names, second names and such and creates a character from that data.

What I am using for that is the following code, which takes all the lines from the text file and places them in an array (This approach has worked well so far):

file=open("file_name","r")
array_name = []
for line in file:
    array_name.append( line.rstrip('\n') )

(Repeat this for every text file)

The sources I take that data from are often badly formatted (Everything in caps, nothing capitalised, etc), so I am trying to create another piece of code that capitalises every single word in all those text files. After extensive searching I've found that title() does exactly what I want to do, and I am trying to implement that approach using part of the previous code.

I am running into some trouble, especially because apparently I have created a piece of code that does what I want but does not actually write the changes to the file. Here is what I have done:

file=open("file_name","r+")
for line in file:
    line=line.title()
file.close

The idea is to open the file in read and write mode, read a line, change that line to the same line with title() applied and repeat until the end of the file.

Am I forgetting to add something? I have been trying things and thinking about it for some time now and I am not able to make this work. I am assuming the problem is in the line=line.title() line, but all my attempts have ended with the text files being empty or screwed up in some other way.

Answer 1

First, use a context manager, the with statement:

with open('file_name', 'r+') as my_file: # this automatically closes it
    lines = my_file.readlines()
    # now, rewrite the data
    for line in lines:
        my_file.write(line.title())

Edit: to completely rewrite the data, you have to use a 'w+' buffer mode (so first you can read it, than write over the original data) and also set the file pointer back to the beginning of the file:

with open('file_name', 'w+') as my_file:
    lines = my_file.readlines()
    # set the file pointer at the beginning of the file
    my_file.seek(0, 0)
    # now, rewrite the data
    for line in lines:
        my_file.write(line.title())

The previous issue (with my first example) is that once you have fully read the file, the file pointer is at the end of the file. Thus, you have to set it back to the beginning using the file.seek method.

Answer 2

def main():
    words = {}
    for whichfile in ['firstname', 'lastname', 'noun', 'adjective']:
        # read all words from file
        with open(whichfile + '.txt') as inf:
            words[whichfile] = [line.strip().title() for line in inf]

        # write capitalized words back to file
        with open(whichfile + '.txt', 'w') as outf:
            outf.write('\n'.join(words[whichfile]))

if __name__=="__main__":
    main()