Parse and evaluate simple math word problems returning the answer as an integer.
Problems with no operations simply evaluate to the number given.
What is 5?
Evaluates to 5.
Add two numbers together.
What is 5 plus 13?
Evaluates to 18.
Handle large numbers and negative numbers.
Now, perform the other three operations.
What is 7 minus 5?
2
What is 6 multiplied by 4?
24
What is 25 divided by 5?
5
Handle a set of operations, in sequence.
Since these are verbal word problems, evaluate the expression from left-to-right, ignoring the typical order of operations.
What is 5 plus 13 plus 6?
24
What is 3 plus 2 multiplied by 3?
15 (i.e. not 9)
The parser should reject:
Sometimes it is necessary to raise an exception. When you do this, you should always include a meaningful error message to indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. For situations where you know that the error source will be a certain type, you can choose to raise one of the built in error types, but should still include a meaningful message.
This particular exercise requires that you use the raise statement to "throw" a ValueError
if the question passed to answer()
is malformed/invalid, or contains an unknown operation. The tests will only pass if you both raise
the exception
and include a message with it.
To raise a ValueError
with a message, write the message as an argument to the exception
type:
# if the question contains an unknown operation.
raise ValueError("unknown operation")
# if the question is malformed or invalid.
raise ValueError("syntax error")
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