OOP & classes

class DataFilter:
    """A beginner-friendly helper to filter lists of dictionaries."""
    
    def __init__(self, data):
        self.data = data
    
    def filter_by(self, key, value):
        """Return items where data[key] == value."""
        return [item for item in self.data if item.get(key) == value]
    
 …

class DataFormatter:
    """Helper class for beginners to format common data types."""
    
    def __init__(self, name="data"):
        self.name = name
        self.records = []
    
    def add_record(self, key, value):
        """Add a key-value record to the formatter."""
        self.records.append({"key": key, …

class DataSorter:
    def __init__(self, data):
        self.data = data

    def sort_numbers(self, reverse=False):
        return sorted(self.data, reverse=reverse)

    def sort_strings_ignore_case(self, reverse=False):
        return sorted(self.data, key=str.lower, reverse=reverse)

    def sort_dicts_by_key(self…

class DataMerger:
    def __init__(self):
        self.records = []

    def add_record(self, record):
        if isinstance(record, dict):
            self.records.append(record)
        else:
            raise TypeError("Record must be a dictionary")

    def merge_by_key(self, key):
        merged = {}
        for …