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You can compare objects. Let's explore how.
Correction
At 8:25 in the video, Craig says " And, of course, that only happens if the age is less than 6." but should have said, " And, of course, that only happens if the age is less than or equal to 6."
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So we just picked up the ability to
check out the equality between objects,
0:00
the double equal sign right?
0:05
So let's explore some more
comparison operations.
0:06
Let's explore these in the shell first,
so we'll say python.
0:10
Now to check and
see if values are not equal,
0:14
we use the exclamation mark and
then equal sign, right?
0:18
So that exclamation mark there
is sometimes called bang,
0:23
you'll hear people say bang.
0:26
So bang equals is not equals.
0:27
So, hot-dogs are not equal to sandwiches.
0:30
True, now unfortunately that's
not solving the age old debate.
0:35
It's just saying that
the strings aren't the same.
0:38
And speaking of an age old debate,
my daughters are 6 and 3.
0:41
You can use the greater than
symbol to compare numbers, so
0:45
6 greater than 3, true.
0:49
And this confirms much of to
the disappointment to my little one,
0:51
that my eldest is indeed older.
0:55
She's greater in age.
0:57
And just to double check we can
do the reverse, is 6 less than 3?
0:59
I'm sorry sweetie.
1:04
So, there will be cases where you'll
want to check if a value is equal to or
1:05
greater than another.
1:11
So you can combine that with
a pretty handy operator,
1:14
you can say, is 42 >= 42?
1:19
And as you can see it compares
each of these operands.
1:24
That's what these values are on both
sides, they're called operands, and this,
1:30
they're being operated
on by this operator.
1:34
It says are they greater than or
equal to each other?
1:36
Now, real quick,
you can do this with strings as well.
1:39
So we could say,
is sunshine greater than rain?
1:44
Which is obviously true, but
that's not why it's returning true.
1:49
This is doing alphabetical order,
s comes after r, it's greater than r.
1:53
So here's how I want to use our new
comparison operators in our program.
1:58
So, what happened was, I showed
this program to my six year old and
2:03
she put in her name and the program
suggested that she start learning Python.
2:06
Which, I obviously totally agree with, but
2:11
she should really learn to read
a little bit better before diving in.
2:13
So, let's do this.
2:17
Assuming first name is an r name or
r fellow student's name,
2:19
we should ask for their age.
2:23
So if it's less than or
equal to, let's say six,
2:26
let's suggest that they learn to
read first and then learn Python.
2:29
So we can do that, right?
2:34
Now, it might not be
completely clear to you, but
2:35
it's totally fine to nest an if statement.
2:38
So let's do that, let's come in here
inside of our else here, right?
2:41
So it's not us, it's not here so,
we don't know who they are.
2:46
So let's go ahead and
say age equals input, how old are you?
2:50
And we'll give some space, and
2:56
now remember that input
always returns a string.
2:59
But we actually need here what we need is
an integer, cuz we're gonna compare to it.
3:04
So, let's coerce what is returned
into an integer and you can do this,
3:08
we can do this by wrapping it.
3:13
We can say int, and then on this other int
here, we can do this, so what's happening
3:15
is we're coercing whatever is returned
from here, which is gonna be a string.
3:19
So we're gonna take the string and
put it into here.
3:24
That make sense?
3:26
So we only want to do this if they
are less than or equal to six.
3:27
So if age is <= 6,
3:34
I'm gonna start my body.
3:38
And we'll say print.
3:42
Wow, you're like five, four, three,
3:45
two [LAUGH] if you're confident
with your reading already.
3:50
And then we'll just go ahead and
say what we were gonna say.
3:57
We gotta format this, we'll push in
the age and that'll automatically happen.
4:00
I'm gonna make sure that
I'm balanced there, okay?
4:04
Great, and so what's gonna happen,
4:06
they will only see this message if they're
less than 6, less than or equal to 6, and
4:09
then it will print and you
should totally learn Python.
4:14
Cool, so let's go ahead,
let's make sure that we save this.
4:17
I'm gonna come in here,
drop out of the console.
4:20
And I will clear and
will say python hello.py.
4:26
So run this with my daughter, her name was
Hattie and hello, Hattie, how old are you?
4:33
So awesome, we're in the else,
we've got a new input here.
4:38
We'll put in 6, which will be a string,
I'll turn it into an int.
4:40
It says wow, you're 6, if you're
confident with your reading already,
4:43
you should totally learn Python,
Hattie, awesome.
4:46
Now if you read this
script from the very top,
4:49
it should be pretty clear
to you what's going on.
4:51
Well, I mean especially
since we wrote it together.
4:53
But, there's a little bit of logic
here that is particular to a use
4:56
case that I just introduced.
5:00
It might be a little confusing as
to why we are asking for age here.
5:02
So there is a concept called comments, and
5:06
what you can do is you can
put in a sentence here.
5:09
So let's do that.
5:13
So to create a comment, you just put in
a pound sign, also known as a hashtag,
5:15
depending on your age.
5:18
And then we just put our comment.
5:20
So we can say, this is just in case we
5:21
have a younger user who can't yet read.
5:26
And comments are great.
5:33
And at this point in your learning
journey, feel free to put them everywhere.
5:35
A lot of students like to take notes for
5:39
the different parts of the program
to write in the comments.
5:40
And that's totally fine.
5:43
You'll see as this language becomes second
nature that you'll probably need fewer
5:44
comments.
5:48
Now comments are great for
5:49
reasoning what might not be
clear to readers of your code.
5:51
However, if you're needing to explain
what a line of code is doing,
5:54
you might want to think about
rewriting that line of code, or
5:57
breaking it down until it's
more easy to understand.
6:01
Writing readable code is a skill
that improves over time and
6:04
we'll build up your skill set together.
6:07
One of the most wonderful things about
Python in particular is how easily
6:10
the language can be read.
6:13
Now part of this readable comes from
the required indentation of the language.
6:15
This code will not work if I
remove some of the indentation.
6:20
So watch this I'll go ahead and
I'll take a little bit of this age off.
6:23
And right away, see how it turned red?
6:27
It's like, stop.
6:29
So I'm gonna go ahead and
save this even though that's red.
6:30
And let's run it and see what happens.
6:34
And you'll see that the error's
actually on line nine, and not line 10.
6:37
And it's saying that there's
an indentation error.
6:44
So what I want you to remember, is to
remember to look around when that happens.
6:46
It's saying 10 but
the error is actually on line nine.
6:50
Let's clear this up.
6:54
Phew, that feels better already.
6:55
Speaking of reading code, what do you
say we read through this one more time.
6:58
So we came in here with Hattie,
and first name now equals Hattie.
7:03
And we say, hello Hattie?
7:07
And then we check to see if first
name is equal to your name,
7:09
it's Craig here in my code.
7:12
And since it doesn't,
we drop down to the next else if.
7:14
And it say is equal to
our student Maximiliane.
7:18
It doesn't, so therefore,
7:22
since none of these if statements
turned out, we run into our final else.
7:24
And that's here, and we ask input
from our user of how old they are.
7:30
And this comment directly above
shows us why we might be doing that.
7:36
The input function
always returns a string.
7:40
And we need to coerce that to an integer,
7:44
because we want to compare
that in our next line here.
7:48
We wanna say, are you less than 6?
7:52
Less than or equal to 6.
7:54
And because of my experience,
7:55
7 is really about the time that you
don't need to focus too much on reading.
7:57
So much growth happens at five and six,
but I don't think you're quite there yet
8:01
reading level wise.
8:05
So this definitely could read less than
seven, which is essentially, less than or
8:06
equal to six, right?
8:10
Now, if that expression was true,
we print out this message.
8:12
And when we call the format string,
we're passing in an integer but
8:18
it's automatically coerced
back into a string for us.
8:21
And, of course, that only happens
if the age is less than or equal to 6.
8:25
Then everybody is
suggested to learn Python.
8:29
And then, finally, have a great day.
8:33
So how'd that feel?
8:36
Did that all make sense?
8:37
Now if it didn't,
let me remind you that you can rewind me.
8:39
Just scrub your video player
back a minute or so, and
8:43
you can walk that code all again.
8:45
Now if it wasn't all crystal clear,
remember, that is totally fine.
8:47
This very well could be your
first time looking at code.
8:52
Think about how much of it
you actually did understand.
8:56
And then try to compare it to what
you knew before we met each other
8:59
way back when in that first video.
9:03
It's kind of a lot of new stuff, isn't it?
9:05
Great job immersing yourself,
stick with it.
9:07
You got this.
9:09
If you have questions please ask them.
9:10
Every one is super nice in the community,
and chances are someone might be having
9:14
the same question that you're having,and
they just haven't asked it yet.
9:18
Check the questions
attached to this video.
9:22
Can you help somebody?
9:24
I want to reiterate that you're
doing great learning the basics.
9:26
Taking input and
then branching to display different output
9:29
based on various conditions is
how most applications work.
9:33
Think about how most websites,
that require you to sign in,
9:37
actually work behind the scenes.
9:40
Now if you aren't logged in, it shows
you the buttons to Login or Sign Up.
9:42
If you click the Login button, the form
shows up, and you input your username and
9:46
password.
9:50
Now, in the case that you are logged in,
it shows your profile picture, but
9:51
you don't see the buttons.
9:55
Think about what that
code might look like.
9:56
If the user is logged in,
we display the user's avatar.
9:59
Otherwise, we need to show the buttons.
10:05
Now that display profile avatar is
a function that we would need to write.
10:08
And we'll get to that in a bit, but
see the branching logic at play.
10:13
See how the output is using a boolean
variable to determine which branch
10:16
should work.
10:20
Also, that login input,
that's just taking input, right?
10:21
Just like our command prompt.
10:25
It returns what the website user entered,
so
10:27
that the values can be
used to log the user in.
10:29
You just learned a bunch of concepts.
10:33
You've got the building blocks that are
present in all sorts of applications that
10:34
you use today.
10:38
I bet you'll start looking at your apps
a little bit differently as you start to
10:39
use them.
10:43
I am excited for what's coming up next.
10:44
We're gonna take a look at
writing our own functions and
10:46
how to use loops to repeat your code.
10:48
I can't wait to get those functions and
10:50
loops added to your ever
growing bag of tricks.
10:52
Let's do this.
10:54
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