如何将二进制字符串转换为十进制？

def binary_to_decimal(binary_string):
    decimal_value = 0
    binary_string = binary_string[::-1]
    for i in range(len(binary_string)):
        if binary_string[i] == '1':
            decimal_value += 2**i
    return decimal_value

binary_string = "1101"
decimal_value = binary_to_decimal(binary_string)
print(decimal_value)  # 输出：13