Convert a price string into a float, handling different formatting styles.

parse_price.py

import re

def parse_price(price: str) -> float:
    """
    Convert a price string into a float, handling different formatting styles.

    - Supports "1,123.23" (English format) -> 1123.23
    - Supports "1123,23" (European format) -> 1123.23
    - Supports "1.123,23" (European thousand separator) -> 1123.23
    - Supports "1,123" (English thousand separator) -> 1123.0
    - Supports "1123" (plain number) -> 1123.0
    - Rejects ambiguous formats

    Raises:
        ValueError: If the format is ambiguous or invalid.
    """
    price = price.strip()
    
    # Check if both '.' and ',' are present
    if '.' in price and ',' in price:
        if price.rfind('.') > price.rfind(','):
            # English format: "1,123.23"
            price = price.replace(',', '')
        else:
            # European format: "1.123,23"
            price = price.replace('.', '').replace(',', '.')
    
    # If only ',' is present, determine if it's a decimal or thousand separator
    elif ',' in price:
        if price.count(',') == 1 and len(price.split(',')[-1]) == 2:
            # Likely a decimal separator (European style)
            price = price.replace(',', '.')
        else:
            # Likely a thousand separator (English style)
            price = price.replace(',', '')

    # If only '.' is present, assume it's a decimal separator
    
    # Ensure the result is a valid number
    if not re.fullmatch(r'\d+(\.\d+)?', price):
        raise ValueError(f"Invalid price format: {price}")

    return float(price)


if __name__ == "__main__":
    # Example usage:
    prices = ["1,123.23", "1123,23", "1.123,23", "1,123", "1123"]
    for p in prices:
        try:
            print(f"{p} -> {parse_price(p)}")
        except ValueError as e:
            print(e)