Using glob for Pattern-Based File Matching

Often, you need to find files that match a certain pattern, such as “all text files” or “all images starting with photo_”.
The glob module provides a convenient way to search for files using wildcard patterns (like those used in Unix/Linux shells).

Key Wildcard Patterns

• * (asterisk) → Matches any number of characters (including zero).
  Example: "*.txt" → matches all files ending in .txt.

• ? (question mark) → Matches exactly one character.
  Example: "data?.csv" → matches data1.csv or dataA.csv, but not data10.csv.

• [ ] (brackets) → Defines a character set or range.
  Example: "[0-9].txt" → matches 1.txt or 7.txt.
  Example: "file[AB].csv" → matches fileA.csv or fileB.csv.

Using glob.glob()

The main function is:

glob.glob(pattern, recursive=False)

• Returns a list of path names matching the pattern.

• By default, it does not search subdirectories unless recursive=True.

Examples:

import glob

# Example 1: Find all Python files in current directory
py_files = glob.glob("*.py")
print(py_files)  
# e.g., ['script.py', 'test_module.py']

# Example 2: Find all CSV files beginning with 'data'
csv_files = glob.glob("data*.csv")
print(csv_files)  
# e.g., ['data1.csv', 'data_results.csv']

# Example 3: Find single-character filenames with .txt
txt_files = glob.glob("?.txt")
print(txt_files)  
# e.g., ['a.txt']

• "*.py" → matches all .py files.

• "?.txt" → matches one-letter or one-digit .txt filenames.

Recursive Glob Searches

To search in subdirectories:

# Find all .txt files in current directory + subdirectories
all_txt = glob.glob("**/*.txt", recursive=True)
print(all_txt)

• **/*.txt → Matches .txt files at any depth.

• recursive=True is required for ** to work.

Note on Hidden Files

• By default, glob does not match hidden files (starting with .).

• To include them, the pattern must start with a dot:
  Example: ".*.txt".

Using pathlib.glob()

If using pathlib, Path objects have:

• .glob(pattern) → non-recursive.

• .rglob(pattern) → recursive.

Example:

from pathlib import Path

for file_path in Path('.').rglob("*.py"):
    print(file_path)

• Works like: glob.glob("**/*.py", recursive=True).

Summary:
glob and pathlib.glob() make finding files by pattern simple and efficient, removing the need for manual directory walking.