Strange output of a very simple code?

Question

I'm very new to python, but I found this strange: Code: I was typing in Sagemathcloud's sageworksheet file:

x=y+1
def f(x):
    return y
x=-1
print(x)
print(f(x))

As an output, I kept getting 7 or sometimes 49, something quite randomnumbers no matter what value of x I input. Any insights please?

P.S. I'm trying to make it look like a code, but I'm, not sure how to do that, for example, def was in the next lmine after I typed: x=y+1.

score 0 · Answer 1 · answered Jun 07 '14 at 17:08

0

If that's the only code you have, then y isn't defined before it is used. y will take the value of what was previously in the memory space it's using - and that may not even be an int which causes the randomness of the numbers you're experiencing.

answered Jun 07 '14 at 17:08

Alex Blundell

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Then why is the following not a problem? x and y are not defined apriori? `{z=[x,y] def f(z): return x+y x=2 y=6 print(f(z)) x=2 y=6}` – Noprogexprnce mathmtcn Jun 07 '14 at 19:36
Seems some kind of crazy error from the sagemathcloud itself, because I just did and got it alright: `y=x-1 def f(x): return y x=8 print(f(x))` – Noprogexprnce mathmtcn Jun 07 '14 at 19:53
I'm not sure, but this code is python, and `x = y + 1` will throw a runtime error, so the SageMathCloud is doing something to correct that, and that something is unpredictable. – Alex Blundell Jun 08 '14 at 09:59
It's interesting that Sage is correcting only for the case z=[x,y], where x and y are not defined, but it's not doing any such correction when I type the program with y=x-1. – Noprogexprnce mathmtcn Jun 12 '14 at 14:39
Also, the following is giving me an error: ` z=[x,y] w=[a,b] def f(z,w): return x+b x=3 y=7 a=5 b=6 print(f(z,w)) ` – Noprogexprnce mathmtcn Jun 12 '14 at 14:42

Strange output of a very simple code?

1 Answers1