Reference library

Files & data

Read and write files safely; parse JSON, CSV, and common text formats.

9 matches
Files & data medium

Create a ZIP Archive of a Folder in Python

Recursively zip all files in a folder into a single archive using the standard library zipfile and pathlib modules.

zipfile pathlib archives
Python
import zipfile
from pathlib import Path

def zip_folder(source_dir: str, archive_path: str) -> None:
    """Zip all files in source_dir recursively into archive_path."""
    source = Path(source_dir)
    with zipfile.ZipFile(archive_path, "w", zipfile.ZIP_DEFLATED) as archive:
        for file_path in source.rglob("*"…
17 0 Open
Files & data medium

Download Files from Internet with Progress Bar in Python

Download a file from the internet while displaying a text progress bar in the terminal.

urllib download progress bar
Python
import urllib.request
import sys

def download_with_progress(url, filename):
    """Download a file with a simple text progress bar."""
    def report_hook(block_count, block_size, total_size):
        downloaded = block_count * block_size
        if total_size > 0:
            percent = min(100, int(downloaded * 100 …
54 0 Open
Files & data medium

How to Automatically Extract Every Archive in a Folder with Python

Walk through a folder and extract all ZIP, RAR, and 7Z archives into separate subdirectories using Python.

zipfile rarfile py7zr
Python
import zipfile
import rarfile
import py7zr
import pathlib

def extract_archives(folder: str):
    """Extract every ZIP, RAR, and 7Z archive in the given folder."""
    folder_path = pathlib.Path(folder)
    for archive_file in folder_path.iterdir():
        suffix = archive_file.suffix.lower()
        try:
           …
40 0 Open
Files & data medium

How to Automatically Merge Hundreds of Excel Files Without Losing Formatting in Python

Merge all .xlsx files in a folder into a single Excel workbook, preserving individual sheet structures with sheet name prefixes.

excel pandas merge
Python
import pandas as pd
from pathlib import Path

def merge_excel_files(folder_path: str, output_path: str) -> None:
    """
    Merge all .xlsx files in a folder into a single Excel file,
    preserving individual sheet structures.
    """
    folder = Path(folder_path)
    excel_files = list(folder.glob("*.xlsx"))
    
…
47 0 Open
Files & data medium

How to Memory Map Large Files Read-Only in Python

This code demonstrates reading only the tail of a large file using a read-only memory map (mmap) to avoid loading the entire file into memory.

mmap file-io memory-efficient
Python
import mmap
import os

def read_tail_with_mmap(filepath, bytes_from_end=64):
    """Read the last bytes of a large file using a read-only mmap."""
    file_size = os.path.getsize(filepath)
    start = max(0, file_size - bytes_from_end)

    with open(filepath, "rb") as f:
        with mmap.mmap(f.fileno(), length=0, a…
13 0 Open
Files & data medium

How to Merge Sorted Chunk Files in Python

Merge multiple sorted text files into one sorted output file using a heap for efficient k-way merging.

heapq merge-sort external-sort
Python
import heapq


def merge_sorted_chunks(chunks, output_path):
    """Merge multiple sorted iterables into single sorted output file."""
    with open(output_path, "w") as out_f:
        # Open all chunk files
        handles = [open(chunk, "r") for chunk in chunks]
        try:
            # Heap of (value, index) tupl…
14 0 Open
Files & data medium

How to Parse Apache Log Files in Python

Parse Apache common log format lines into structured dictionaries using Python's standard library.

apache regex log-parsing
Python
import re
from pathlib import Path

def parse_apache_line(line):
    pattern = r'^(\S+) (\S+) (\S+) \[([^\]]+)\] "(\S+) (\S+) (\S+)" (\d{3}) (\S+)'
    match = re.match(pattern, line)
    if not match:
        return None
    ip, ident, user, timestamp, method, path, protocol, status, size = match.groups()
    return …
15 0 Open
Files & data medium

Read Parquet-Like Columnar CSV Chunks in Python

A Python generator that reads a CSV file column-by-column, yielding dictionary chunks where each key points to a list of values—mirroring how Parquet stores data columnar.

csv columnar generator
Python
```python
import csv
from pathlib import Path
from typing import Iterator, List

def read_parquet_like_columnar(csv_path: str, column_names: List[str], chunk_size: int = 2) -> Iterator[dict]:
    """Read CSV data in columnar chunks, similar to how parquet stores columns."""
    csv_file = Path(csv_path)
    with csv_f…
13 0 Open
Files & data medium

Tail last N lines of growing log file in Python

Prints the last n lines of a log file and follows new content appended to it, polling for size changes.

log-file file-handling polling
Python
import time
from pathlib import Path

def tail_log(file_path, n=10, poll_interval=1.0, timeout=10):
    """
    Print the last n lines and follow new lines appended to a growing log file.
    """
    path = Path(file_path)
    # Read the last n lines from the current file
    with path.open("r", encoding="utf-8") as f…
13 0 Open

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