Hard to believe but why can't I do maths?

[Shintaro]

Hi Everyone,

New here and been reading up on the engine, even made a story etc so far very impressed with engine and want to do more with it.

But I want to do a simple bit of maths ... and I haven't found out how to do the following (done lots of searching etc) and I can make characters bounce and put in new buttons and show movies but I can't do maths!!!!!

Basic idea is this ...

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 $ x = renpy.input("Please enter a NUMBER: ")       #This works

Next take the input and treat it as a numeric and multiply it by itself (without going into python - haven't made that work either)

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$ xx = x*x   #Doesn't work

or

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$ xx = %(x)d*%(x)d   #Doesn't work and various variants

What simple bit of arcane insight am I missing?

Cheers


PS How many PyTom's are there really? No on can do all the stuff he does and have a job!!!

[PyTom]

Basically, renpy.input reads in strings. Python is a strongly typed language, so you can't multiply two strings together. (What is "pantsu" * "ninja"?) You need to turn those strings into numbers for them to work.

In Python, there are two types of numbers, ints and floats. Ints are integers, whole numbers, numbers like -1, 0, 1, and 42. Floats are numbers that might have a fractional part**, like -1.0, 0.5, 42.69, 70.0 and so on.

To turn variable x into an int, run the int() function on it:

x = int(x)

To turn it into a float, use float:

x = float(x)

Note that (for most operations) int op int is an int, while anything involving a float is a float. For example:

3 / 2 == 1
3.0 / 2 == 1.5
3 / 2.0 == 1.5
3.0 / 2.0 == 1.5

*Complex numbers are the devil's work, I say! And we're still on 2.3, which doesn't have decimals.

** Although it may not be possible for the computer to represent those fractions precisely.

[Enerccio]

What is "pantsu" * "ninja"?

2x2 Shinobuden?

[themocaw]

All right, so here is a related question.

Let's say I've got two stats: A and B. And I want to use both A and B, but I also want a third stat, C, which is equal to A minus B. How would I set that up using the functions you describe?

[PyTom]

$ c = a - b

In every place where a or b is updated. (Trying to make this sort of thing automatic is actually the subject of my forum spam.)

[Tayruh]

I'm new to Renpy, but doesn't python let you use getters and setters? I would assume it'd be easy to make C automatically update if you put a setter on A and B. It's overly complicated for most people though, I know..

[Tayruh]

Oops. I'm silly. Putting a getter on C would be a much smarter idea.

[themocaw]

$ c = a - b

In every place where a or b is updated. (Trying to make this sort of thing automatic is actually the subject of my forum spam.)

It might actually be easier to do it just before every place that c is checked for. . . anyway. Thanks for the heads up.