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Errors & debugging

Handle failures gracefully, raise helpful errors, and debug with confidence.

3 matches

How to Catch KeyError with a Default Value in Python Dictionaries

Safely retrieve dictionary values while catching KeyError and handling None values by returning a default.

def get_value(data, key, default=None):
    """
    Safely get a value from a dictionary, returning a default if the key
    is missing or the value is None.
    """
    try:
        value = data[key]
        return value if value is not None else default
    except KeyError:
        return default


if __name__ == "_…

13 0 Open

Errors & debugging medium

How to Diff Two Dicts in Python for Config Drift

Recursively compare two dictionaries and report added, removed, and changed keys with their old and new values for debugging configuration drift.

dict diff config

Python

def diff_dicts(a, b, path=""):
    differences = []

    for key in a.keys() | b.keys():
        new_path = f"{path}.{key}" if path else key

        if key not in a:
            differences.append((new_path, "<missing>", b[key], "added"))
        elif key not in b:
            differences.append((new_path, a[key], "<…

12 0 Open

Errors & debugging easy

How to check for None and raise helpful errors in Python

A defensive function that explicitly validates data, keys, and values — raising descriptive ValueError and KeyError exceptions before returning a result.

none error-handling validation

Python

def get_value(data, key):
    if data is None:
        raise ValueError("data cannot be None")
    if key not in data:
        raise KeyError(f"key '{key}' not found in data")
    result = data[key]
    if result is None:
        raise ValueError(f"value for key '{key}' is None")
    return result


if __name__ == "__…

15 0 Open

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