Chunky

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A python module to handle reading and writing of text files in chunks. Automatically creates files when the specified chunk size is reached. It provides a familiar interface of io.TextIOBase for easy integration with existing python IO facilities.

Installation

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pip install chunky

Usage

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Writing files

Chunky creates files based on the specified pattern. The placeholder '{0}' starts with '0' for the first file and is incremented each time the number of lines reaches the specified chunk size.

Below example creates 3 files with names:

• a_file_0.txt - 10 lines
• a_file_1.txt - 10 lines
• a_file_2.txt - 5 lines

import chunky

fileobj = chunky.open("a_file_{0}.txt", "w", chunk_size = 10)
for i in range(0, 25):
    fileobj.write("%d\n" % i)

fileobj.close()

Reading files

Reading is quite straightforward. Based on the specified pattern each file is read starting from chunk 0.

import chunky

with chunky.open("a_file_{0}.txt","r") as f:
    for line in f:
        print line

Callbacks

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Chunky accepts callback functions to notify start and close of a chunk.

• cb_chunk_closed(filename, num_lines_written)
• cb_chunk_start(filename)

import chunky

def closed_callback(filename, num_lines_written):
    print "wrote %d lines in file:%s" % (num_lines_written, filename)

def start_callback(filename):
    print "writing to file:%s" % filename

writer = chunky.open(
    "test_{0}.txt", 'w', chunk_size=10,
    cb_chunk_closed=closed_callback,
    cb_chunk_start=start_callback)

for i in range(0, 35):
    writer.write("%d\n" % i)

writer.close()