How to split big compressed text file to small text files-CodePudding

I want to convert this corpus hu.txt.xz 15GB which becomes around 60GB after unpacking to small versions of text files, each file with less than 1GB or 100000 lines

The expected output: 
     | siplit_1.txt
     | siplit_2.txt
     | siplit_3.txt
        .....
     | siplit_n.txt

I have this script on a local machine but doesn't work it just loads without process because bigdata as I think :

import fun
import sys
import os
import shutil
#  //-----------------------
# Retrieve and return output file max lines from input
def how_many_lines_per_file():
    try:
        return int(input("Max lines per output file: "))
    except ValueError:
        print("Error: Please use a valid number.")
        sys.exit(1)

#  //-----------------------
# Retrieve input filename and return file pointer
def file_dir():
    try:
        filename = input("Input filename: ")
        return open(filename, 'r')
    except FileNotFoundError:
        print("Error: File not found.")
        sys.exit(1)


#  //-----------------------
# Create output file
def create_output_file_dir(num, filename):
    return open(f"./data/output_{filename}/split_{num}.txt", "a")


#  //-----------------------
# Create output directory
def create_output_directory(filename):
    output_path = f"./data/output_{filename}"
    try:
        if os.path.exists(output_path):  # Remove directory if exists
            shutil.rmtree(output_path)
        os.mkdir(output_path)
    except OSError:
        print("Error: Failed to create output directory.")
        sys.exit(1)

def ch_dir():
    # Print the current working directory
    print("Current working directory: {0}".format(os.getcwd()))
    # Change the current working directory
    os.chdir('./data')
    # Print the current working directory
    print("Current working directory: {0}".format(os.getcwd()))
#  //-----------------------
def split_file():
    try:
        line_count  = 0 
        split_count = 1 

        max_lines = how_many_lines_per_file()

        # ch_dir()
        input_file  = fun.file_dir()
        input_lines = input_file.readlines()

        create_output_directory(input_file.name)
        output_file = create_output_file_dir(split_count, input_file.name)

        for line in input_lines:

            output_file.write(line)
            line_count  = 1

            # Create new output file if current output file's line count is greater than max line count
            if line_count > max_lines:
                split_count  = 1
                line_count = 0

                output_file.close()

                # Prevent creation of an empty file after splitting is finished
                if not len(input_lines) == max_lines:
                    output_file = create_output_file_dir(split_count, input_file.name)

    # Handle errors
    except Exception as e:
        print(f"An unknown error occurred: {e}")

    # Success message
    else:
        print(f"Successfully split {input_file.name} into {split_count} output files!")


#  //-----------------------
if __name__ == "__main__":
    split_file()

Is there any python script or deep learning tool to split them for using the to next task

CodePudding user response：

By calling readlines() on the input file handle, you are reading (or trying to) the whole file into memory at the same time. You can do this instead to process the file one line at a time, never having more than a single line in memory:

    input_file  = fun.file_dir()

    ...

    for line in input_file:
        ...

Another issue to be aware of is that this line:

if not len(input_lines) == max_lines:
    output_file = create_output_file_dir(split_count, input_file.name)

is likely not doing what you think it is. Neither input_lines or max_lines will ever change inside the loop, so this will either always create a new file or never will. Unless you happen to process a file with exactly max_lines lines in it, this will always be true. This is not a big deal, but I think as your code is now you're going to end up with an extra empty file. You need to change the logic anyway, so you'll have to rethink how to make this work.

UPDATE:

Here's how I would modify the logic to do the right thing regarding opening each of the output files:

input_file = fun.file_dir()

# output_file = create_output_file_dir(split_count, input_file.name)
output_file = None

...

for line in input_file:

    # Open a new output file if we don't have one open
    if not output_file:
        output_file = create_output_file_dir(split_count, input_file.name)

    output_file.write(line)
    line_count  = 1

    # Close the current output file if the line count has reached its max
    if line_count > max_lines:
        split_count  = 1
        line_count = 0

        output_file.close()
        output_file = None

The key idea here is that you can't know if you need a new output file until you have tried to read the next line after closing the current output file. This logic only opens an output file when it has a line to write out and there is no open output file.

CodePudding user response：

You're trying to allocate a big file into memory which is not possible.

Instead of reading all the content at once just read line by line and process it.

I've fixed the bug seen by @CryptoFool

import fun
import sys
import os
import shutil
#  //-----------------------
# Retrieve and return output file max lines from input
def how_many_lines_per_file():
    try:
        return int(input("Max lines per output file: "))
    except ValueError:
        print("Error: Please use a valid number.")
        sys.exit(1)

#  //-----------------------
# Retrieve input filename and return file pointer
def file_dir():
    try:
        filename = input("Input filename: ")
        return open(filename, 'r')
    except FileNotFoundError:
        print("Error: File not found.")
        sys.exit(1)


#  //-----------------------
# Create output file
def create_output_file_dir(num, filename):
    return open(f"./data/output_{filename}/split_{num}.txt", "a")


#  //-----------------------
# Create output directory
def create_output_directory(filename):
    output_path = f"./data/output_{filename}"
    try:
        if os.path.exists(output_path):  # Remove directory if exists
            shutil.rmtree(output_path)
        os.mkdir(output_path)
    except OSError:
        print("Error: Failed to create output directory.")
        sys.exit(1)

def ch_dir():
    # Print the current working directory
    print("Current working directory: {0}".format(os.getcwd()))
    # Change the current working directory
    os.chdir('./data')
    # Print the current working directory
    print("Current working directory: {0}".format(os.getcwd()))
#  //-----------------------
def split_file():
    try:
        line_count  = 0 
        split_count = 1 

        max_lines = how_many_lines_per_file()

        # ch_dir()
        input_file  = fun.file_dir()

        create_output_directory(input_file.name)
        output_file = create_output_file_dir(split_count, input_file.name)

        for line in input_file:

            output_file.write(line)
            line_count  = 1

            # Create new output file if current output file's line count is greater than max line count
            if line_count > max_lines:
                split_count  = 1
                line_count = 0

                output_file.close()

                # Prevent creation of an empty file after splitting is finished
                if not line_count == max_lines:
                    output_file = create_output_file_dir(split_count, input_file.name)

    # Handle errors
    except Exception as e:
        print(f"An unknown error occurred: {e}")

    # Success message
    else:
        print(f"Successfully split {input_file.name} into {split_count} output files!")


#  //-----------------------
if __name__ == "__main__":
    split_file()