How do I apply my python code to all of the files in a folder at once, and how do I create a new name for each subsequent output file?

问题

The code I am working with takes in a .pdf file, and outputs a .txt file. My question is, how do I create a loop (probably a for loop) which runs the code over and over again on all files in a folder which end in ".pdf"? Furthermore, how do I change the output each time the loop runs so that I can write a new file each time, that has the same name as the input file (ie. 1_pet.pdf > 1_pet.txt, 2_pet.pdf > 2_pet.txt, etc.)

Here is the code so far:

path="2_pet.pdf"
content = getPDFContent(path)
encoded = content.encode("utf-8")
text_file = open("Output.txt", "w")
text_file.write(encoded)
text_file.close()

回答1:

Create a function that encapsulates what you want to do to each file.

import os.path

def parse_pdf(filename):
    "Parse a pdf into text"
    content = getPDFContent(filename)
    encoded = content.encode("utf-8")
    ## split of the pdf extension to add .txt instead.
    (root, _) = os.path.splitext(filename)
    text_file = open(root + ".txt", "w")
    text_file.write(encoded)
    text_file.close()

Then apply this function to a list of filenames, like so:

for f in files:
    parse_pdf(f)

回答2:

The following script solve your problem:

import os

sourcedir = 'pdfdir'

dl = os.listdir('pdfdir')

for f in dl:
    fs = f.split(".")
    if fs[1] == "pdf":
        path_in = os.path.join(dl,f)
        content = getPDFContent(path_in)
        encoded = content.encode("utf-8")
        path_out = os.path.join(dl,fs[0] + ".txt")
        text_file = open(path_out, 'w')
        text_file.write(encoded)
        text_file.close()

回答3:

One way to operate on all PDF files in a directory is to invoke glob.glob() and iterate over the results:

import glob
for path in glob.glob('*.pdf')
    content = getPDFContent(path)
    encoded = content.encode("utf-8")
    text_file = open("Output.txt", "w")
    text_file.write(encoded)
    text_file.close()

Another way is to allow the user to specify the files:

import sys
for path in sys.argv[1:]:
    ...

Then the user runs your script like python foo.py *.pdf.

回答4:

You could use a recursive function to search the folders and all subfolders for files that end with pdf. Than take those files and then create a text file for it.

It could be something like:

import os

def convert_PDF(path, func):
    d = os.path.basename(path)
    if os.path.isdir(path):
        [convert_PDF(os.path.join(path,x), func) for x in os.listdir(path)]
    elif d[-4:] == '.pdf':
        funct(path)

# based entirely on your example code
def convert_to_txt(path):
    content = getPDFContent(path)
    encoded = content.encode("utf-8")
    file_path = os.path.dirname(path)
    # replace pdf with txt extension
    file_name = os.path.basename(path)[:-4]+'.txt'
    text_file = open(file_path +'/'+file_name, "w")
    text_file.write(encoded)
    text_file.close()

convert_PDF('path/to/files', convert_to_txt)

Because the actual operation is changeable, you can replace the function with whatever operation you need to perform (like using a different library, converting to a different type, etc.)

来源：https://stackoverflow.com/questions/31545980/how-do-i-apply-my-python-code-to-all-of-the-files-in-a-folder-at-once-and-how-d