On 28 April 2015 at 22:40, Cameron Simpson <c...@zip.com.au> wrote:
>
> As with all things, sometimes that cannot be reasonably achieved, but it
> is usually so.
>
> We can pick over your code as well if you like. Should we?
>
> Cheers,
> Cameron Simpson <c...@zip.com.au>
Sure, but let me include the full working program after fixup. Although I
still have to write another program to feed it random problems to work it
out. It's a bit spacey, but I ran it through the pep8 program and it
suggested that. I think two spaces between such tiny functions is overkill,
though.
"""
Takes the name of a binary math operation and two numbers from input,
repeatedly, and displays the results until done
"""
def add(a, b):
return a + b
def subtract(a, b):
return b - a
def minus(a, b):
return a - b
def multiply(a, b):
return a * b
def divide(a, b):
return a / b
operations = {'add': add, '+': add, 'plus': add, 'subtract': subtract,
'subtracted': subtract,
'-': minus, 'minus': minus, 'multiply': multiply, '*':
multiply, 'multiplied': multiply,
'times': multiply, 'divide': divide, '/': divide, 'divided':
divide}
def test_number(astring):
"""
Input: A string that should represent a valid int or float. Output:
An int or float on success. None on failure.
"""
for make_type in (int, float):
try:
return make_type(astring)
except ValueError:
pass
return None
def parse_string(math_string):
"""Input: A math string with a verbal or mathematical operation
and two valid numbers to operate on. Extra numbers and operations
are ignored. Output: A tuple containing a function corresponding
to the operation and the two numbers. Returns None on failure.
"""
operation = None
tokens = math_string.split()
numbers = []
for token in tokens:
if token in operations:
operation = operations[token]
elif test_number(token) != None:
numbers.append(test_number(token))
if len(numbers) > 1:
break
if operation is None or len(numbers) < 2:
return None
else:
return operation, numbers[0], numbers[1]
instructions = '''Enter two numbers and one of the four basid math
operations,
either mathematical or verbal. i.e. 3 + 2, 12 divided by 14, 10 minus 4,
etc.
Enter done to quit.
'''
try:
user_input = input(instructions)
while True:
if user_input == 'done':
break
result = parse_string(user_input)
if result == None:
print("Not a valid math operation.")
else:
func, num1, num2 = result
print(func(num1, num2))
user_input = input()
except KeyboardInterrupt:
print("Program terminated by user")
--
Jim
If you only had one hour left to live, would you spend it on Facebook,
Twitter, or Google Plus?
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