File I/O

def find_files(substring, path, recursive=True, check_ext=None, ignore_invisible=True):
    """
    Find files matching specified criteria.
    
    Parameters:
    - substring: str, substring that must be in filename
    - path: str, directory path to search in
    - recursive: bool, search subdirectories recursively
    - check_ext: str, file extension to filter by (e.g., '.txt')
    - ignore_invisible: bool, ignore hidden files (starting with '.')
    
    Returns:
    - matching_files: list, list of file paths matching criteria
    """

def find_filegroups(paths, substring='', extensions=None, ignore_invisible=True):
    """
    Group files by specified criteria from multiple paths.
    
    Parameters:
    - paths: list, list of directory paths to search
    - substring: str, substring filter for filenames
    - extensions: list, list of file extensions to include
    - ignore_invisible: bool, ignore hidden files
    
    Returns:
    - file_groups: dict, dictionary grouping files by criteria
    """

from mlxtend.file_io import find_files, find_filegroups
import os

# Find all Python files in current directory
python_files = find_files(
    substring='',
    path='.',
    recursive=True,
    check_ext='.py',
    ignore_invisible=True
)
print(f"Found {len(python_files)} Python files")

# Find files with specific substring
config_files = find_files(
    substring='config',
    path='.',
    recursive=True,
    ignore_invisible=True
)
print(f"Found {len(config_files)} files containing 'config'")

# Group files by extensions
file_groups = find_filegroups(
    paths=['.', './docs'],
    extensions=['.py', '.md', '.txt'],
    ignore_invisible=True
)
print("File groups by extension:")
for ext, files in file_groups.items():
    print(f"  {ext}: {len(files)} files")