如何阅读文本文件，然后使用python将其拆分为多个文本文件？

Question

I'm given a text file daily. I need to do a couple things to the text file.

1. I need to insert a line break every 181 characters.

2. I need to read the text file line by line and send individual lines to new text files. These files can contain different data types per line, which for my system is unusable. For example, I might get a file tomorrow that has 250 lines of data, containing 6 different data types. The data types are determined by the first four letters of the line. I need to read each line, and if the line starts with ABC1, send it to text file "ABC1.txt". The next iteration and all lines that start with ABC1 need to be appeneded into the same "ABC1.txt" file. If the line starts with "ABC2" send it to text file ABC2.

In the end I need to take original_file.txt, and split it up into ABC1.txt, ABC2.txt, ABC3.txt, ABC4.txt.

I'm new to programming and I'm fiddling around with it. Currently I can open the file and read it, and I can print it to a new file. I haven't figured out how to sort the lines into the lines I need, then send those to the new text file, then repeat that for the other file types. I've done a lot of googling and watched a lot of videos but none seem to do what I'm trying to do, they're all pretty generic.

I would also like to figure out how to turn this fixed length document into a csv, but that would just be icing on the cake.

Answer 1

The first thing you are going to need to learn is handling files in Python. This link is a good start for beginners:

http://www.pythonforbeginners.com/files/reading-and-writing-files-in-python

A csv file is just a file with Comma Separated Values and should be easy enough to figure out when you have some basic Python file handling under your belt. Open a csv file in a text editor to see what I mean.

Answer 2

Use a to append the files each time use if/elif checks to see what each line startswith.

with open('original_file.txt', 'r') as infile,open("ABC1.txt","a") as ab1,open("ABC2.txt","a") as ab2,\
    open("ABC3.txt","a") as ab3,open("ABC4.txt","a") as ab4:
        for line in infile:
            if line.startswith("ABC1"):
                ab1.write(line)
            elif line.startswith("ABC2"):
                ab2.write(line)
            elif line.startswith("ABC3"):
                ab3.write(line)
            elif line.startswith("ABC4"):
                ab4.write(line) 

If you want to insert something every 181 chars, this should be close to what you want:

def insert_break(s,n, br):
    while s:
        yield "{}{}".format(s[:n],br)
        s = s[n:]
with open('output.txt', 'r') as f,open('updated.txt', 'a') as f1:
    inserted= "".join((insert_break(f.read(),181,"\n")))
    f1.write(inserted)

with open('updated.txt', 'r') as infile,open("ABC1.txt","a") as ab1,open("ABC2.txt","a") as ab2,\
        open("ABC3.txt","a") as ab3,open("ABC4.txt","a") as ab4:
            for line in infile:
                print line.startswith("ABC1"),line
                if line.startswith("ABC1"):
                    ab1.write(line)
                elif line.startswith("ABC2"):
                    ab2.write(line)
                elif line.startswith("ABC3"):
                    ab3.write(line)
                elif line.startswith("ABC4"):
                    ab4.write(line)

If you want to find if a substring is in your string use if "your_sub_s" in line: