Does the if sentence on python execute only once?

Question

im new on this, and im using an if statement to load an image in case X thing happens, this is my code:

if  self.puntos > 0:
        self.fondo = load_image('Fondo2.png', IMG_DIR)
        self.primera_vez = True

So when puntos (points) get over 0 the background changes, the problem is that the new image loads constantly causing low framerates, is this because the if statement executes constantly or what? Thanks

There is no possible way of knowing that from these 3 lines of code. But this "if" as shown will only execute once. — Idos, Jan 30 '19 at 01:00
This code will only execute once, unless it's inside a loop. — John Gordon, Jan 30 '19 at 01:02
that if is inside a definition that includes a bunch of other statements that work correctly, but of course they are all separated, no idea why the image loads constantly — MrBean, Jan 30 '19 at 01:04
It will load the image every time it executes, if `self.puntos` is greater than 0. It doesn't automatically only execute when `self.puntos` changes from less than to more than zero. — Blorgbeard, Jan 30 '19 at 01:06
Generally speaking, you should load *all* your images when your program first starts -- that way they're already decompressed and in memory when you need them. — Charles Duffy, Jan 30 '19 at 01:07
I'm assuming this code is in the main loop, so yes, it will be executing every time. Do what @Charles suggests - before the main loop, put `img_fondo2 = load_image('Fondo2.jpg', IMG_DIR)`, then you can change the line in your `if` statement to `self.fondo = img_fondo2`, and it will be much faster. — Blorgbeard, Jan 30 '19 at 01:11
@Blorgbeard that's what i think is happening, is there any way to make the image change only once? — MrBean, Jan 30 '19 at 01:11
Every statement executes once, unless another part of the program tells it to execute again. e.g. a statement inside a function gets called once, *every time that function is called*, a statement inside a loop gets called *every time that loop is rerun*, and a statement in an if runs *only if the logical expression evaluates to true*. — 3D1T0R, Jan 30 '19 at 01:15
Please [edit] your question to give more context to this code. — 3D1T0R, Jan 30 '19 at 01:19
@3D1T0R ok thanks for the comment, if i don't put that line the new background appears only where the different character's sprites are, for example i have my character wich i move and as i move it around the screen it starts showing the image where the sprite has been, till every space has been covered by any character — MrBean, Jan 30 '19 at 01:40

score -3 · Answer 1 · answered Jan 30 '19 at 01:05

-3

Yes, you want to look to put the same code in a while block.

while self.puntos > 0:
        self.fondo = load_image('Fondo2.png', IMG_DIR)
        self.primera_vez = True

then when self.puntos is not > 0 it won't render

answered Jan 30 '19 at 01:05

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This is *worse* than the original -- the OP was complaining that they were seeing performance that implied that `load_image` was running more than once; now you're *ensuring* that it does so, even if the rest of their program is corrected! – Charles Duffy Jan 30 '19 at 01:07

Does the if sentence on python execute only once?

1 Answers1