Hi, welcome to this new video. In this video, we're going to start learning
about probability. This is going to be a very, very simple introduction
to probability. This is not again a
probability course, but within design, it's useful to have certain
understanding of how we could actually use probability
for determining variation. What do we mean by probability? Probability is a mathematical
concept that helps us quantify the likelihood
of certain events. When we start using the idea of a distribution or a
probability distribution, we start thinking of a statistical function
that describes all the possible values
and likelihoods of those values to happen
within a given range. What do we mean by all
the possible outcomes, i you start thinking of, let's say all the
possible circles, as you can see in the
drawing on the right, maybe we have a total number of nine circles and maybe the number of desired
outcomes is two. We can start thinking, what is the
probability of having two items maybe fitting
up certain criteria? Perhaps we would perform a different code
for those items. It's important to
know that we are evaluating in relation to the totality of the
possible outcomes. A simple way of thinking of probability is
through percentages, and we could start by
creating a random number. We know the function random, and if we start thinking
of a random value 0-1 obviously considering
decimal places, we can quickly make a bit of math to
understand the percentage, if we would say
something that is less than 0.75 that
means that there's going to be a roughly 75%
chance of an event to occur. If we actually say bigger
than 0.75 in such condition, we would have a 25%
of that happening. This is not going
to be exact because when we're using a random value, the random value will be
different every time. You're not having
exactly the 75, 25, there is going to be
a small variants there. But especially when we're
thinking of large populations, let's say we have hundreds
of elements in the screen, we can rely that we can operate with a sense
of probability. Let's say we want to color
some of those items, like 25% of those items, differently than the rest. This is where probability can actually play
out very nicely. Let's look at an example code. Here we go. We
have our template. Let's start by creating a
loop, like a four loop. Because I would like to work
with a range of elements. Four range, 0-100. A little bit of a
different language there. What we're going to do
is create an ellipse, a circle, basically in a
random location in the screen, so let's say x. If we want to use, let's
always remember to import the random
module up here. Let's do that uniform. Uniform here, because I want
all the decimal places. If I want to distribute
the ellipses, I'm going to draw ellipses basically everywhere
in the Canvas. I'm going to do a random value between zero and the
size of the screen. The x, it's going to be between zero and the
size of the screen. We can copy this line
for the y variable. We're going to create two
variables on x and y, and let's use the
height of the screen, in this case here. Now we can actually
draw our ellipse. Ellipse x, y, and the size, it doesn't matter. We can do 20, 20. At this point, we should have
100 ellipses in the screen. Let's just make sure
that we're going to do feel white at the moment
and maybe no stroke. Let's see if we're not
having any errors. We have 100 of those.
That's all good. Let's imagine that we want to use this notion of randomness
and probability to color red or change the color of the ellipses to 25% or 20% of them, a particular
percentage. The first thing
we're going to do is create a random value. Random number. This is
going to be a variable. We can here use random.uniform
between zero and one. If we print this value, let's just print it first
to see what we're getting. Every time you're using random, maybe you're not
so sure yet about the different versions of
random that are out there, you can certainly go and
read the documentation. But you see that we're getting a different
decimal place value. It's unlikely that
we're going to get one exactly or zero exactly, but because we have so
many decimal values. But we have a
distribution of values. Now we can comment out
this print statement. For each one of
those 100 ellipses, we have a random value
assigned to each one of them. Let's do an if statement. Remember that every time we're looping through one
version of the loop, we're creating a
new random value and we're going to be
evaluating it differently. So if this random value
is bigger than 0.2, so let's give 80% chance of
the first event to occur. We're going to add
here some code. Then let's say else and here
we can do some other code. What kind of code do we want? I think that for now I'm going to obviously
leave that door open for you to explore graphically something
more interesting. Just let's change the field. Let's say if it's bigger
than 0.2 meaning that 80% of the ellipses
are going to be white and maybe 20% of
them are going to be red. Let's look at that.
As you can see, if you count, maybe sometimes
you'll see 21 or 19, or 18. The random doesn't really give
us an exact distribution, but roughly speaking,
we should be having 20% of our ellipsis being
in the second color. I think this is the beauty of working, especially in design, working with probability,
you're designing probabilistically. You're
not exactly saying where the red spheres are, or the total number of them. But you're roughly having
a composition between an 80% of white spheres
and a 20% of red ones. There's a lot of
interesting ideas that come from thinking,
probabilistically in design. If you want this distribution
to be more equal, like 50% like a 50/50, you can actually put a
0.5 here. There you go. You should have a
balance number. If you actually
bring this value up, right, somewhere to maybe 500, because we're generating a
random value every time, we are not depending
on this value. This number could be any number: it could be 1,000,
it could be 300. We're always going to get
a 50/50% distribution in this case because
we are actually evaluating a value
between zero and one, and we're cutting it halfway. We're going to be using
this technique quite a bit in the future, but again, this is the
introduction to this concept. Here we have again 20%
and again I invite you to play by increasing this
number to a much larger. Again, the point is not to count and see if this is
right or wrong. But it's roughly having a sense, am I getting a 20%? It might so happen
that you're actually having some spheres
on top of each other, so it might be very difficult
to evaluate precisely. You could create
a counter to see how many variable that counts. If this condition is true, I'm counting plus one. If second condition is true, you count plus one
in the other one, and you would see if in fact what is the final count
after you on the loop. But again, that could be a little bit of an
extra assignment that you can try on your own. We're going to leave this video here and I'll see
you in the next one. We're going to
continue looking at different functions for design.