element_data.py 文件源码

def symbols_to_numbers(symbols):
    """Given element symbol(s), return the atomic number(s) (number of protons).

    Args:
        symbols (str or list of str): Atomic symbol(s).

    Returns:
        ndarray: Atomic number(s) (number of protons).

    Raises:
        ValueError: If a given atomic symbol is invalid and doesn't have a
        corresponding number.
    """
    single_value = False
    if isinstance(symbols, (str, np.str_)):
        symbols = [symbols]
        single_value = True
    numbers = []
    for symbol in symbols:
        number = SYMBOL_TO_NUMBER_MAP.get(symbol)
        if number is None:
            raise ValueError(
                "Given atomic symbol {} is invalid and doesn't have a number "
                "associated with it.".format(symbol)
            )
        numbers.append(number)
    return numbers[0] if single_value else np.array(numbers)