WEBVTT

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So continuing on from the previous
video in our introduction to Python, so

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we've learned about the print command and

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we've learned a little bit about streams
and a little bit about operators and

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a little bit about adding numbers and
so forth together.

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And let's now use another function.

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So what we can do to make
this a bit easier and

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a bit more useful is we can
create a way to actually show

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a name that's entered from
the keyboard on the screen.

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So what I'm gonna do is I'm gonna
delete this other code that has

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already been used,
cuz we don't need that anymore.

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Complete delete all that and
we're gonna start by typing greeting.

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And greeting again is
the name of our variable,

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I will be talking more
about variables shortly.

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Hello.

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We can type name = input
("Please enter your name ").

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Then we can type print(greeting + notice
I've added a space there, plus Name.

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And we just run that to see what it does.

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And the other thing is once you
actually have got the run window open,

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and we don't need to right click,
although we can run it that way,

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you can also just come over here and click
on the green arrow and run it that, so

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it's asking us to please enter our name.

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I can type in Tim, press enter, and
it actually comes up and says, Hello Tim.

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So it's actually looked
at what we've typed, and

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it's recorded that into
this variable called name.

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And the message has then printed the
greeting, which is hello, another space,

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then added what we've typed,
which is in this case, name.

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So essentially as you saw, the input
function displays the text that's

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been provided to it then waits for
text to be entered into the keyboard.

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So, in other words, display this
message: please enter your name,

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then waited until we typed something,
then we actually pressed enter.

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The text, at that point, you typed is
stored in the variable name as a set, and

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that's used by the print function
to actually show the greeting.

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Now in terms of strings there's
also a special character called

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the backslash character.

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That's actually got a special meaning
in strings, so it's used to escape

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the character that follows it to
give that character special meaning.

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So there's lots of different
control characters, and

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we won't go through them all now.

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But some of them will actually
do things like start a new line,

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or provide a tab to actually
provide tabbed output.

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So let's just go through and
look at a couple of those.

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So we can type something like

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'splitString = "This string

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has been, I am typing \nsplit

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over \nseveral\nlines"'.

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And if we print that.

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And that's when I typed the first
few characters of the variable,

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IntelliJ quite nicely comes up and
says, or do you mean splitString.

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So again if you want that, you don't
have to type the whole variable name.

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You can just press enter at that point,
and it actually puts the rest in for

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us automatically.

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So if I run that, or actually I need to
finish off that from the last one, so

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I'll pop my name in.

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I can see how that worked, and let me just
actually delete this first part up here.

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Actually what I'll do,
is I'll actually comment it out.

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So I can press Cmd+Slash on my Mac, and
notice how I put the slashes in, and

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down at the bottom it tells you
if press Ctrl+Slash on Windows or

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Linux machines it'll do the same.

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So, what I've done is I've
commented that code out,

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which means that that now won't run.

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Because, remember, a comment is
there purely for your reference.

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So if I run this again,

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we'll finally get straight to this
little example of the string.

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So you can see what's happened in this,

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\n has actually caused the cursor
to start on the next line.

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So consequently, for each one of
those \n's we added that actually

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spit onto a separate
line each time we did it.

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We could do something
similar with a tab string.

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So if we type tabbedString =
"1\t2\t3\t4\t5" and another tab again.

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And if we do print tabbedString,
if you run that,

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you can see how that's done
something a little bit different.

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It's used a standard tab function
which you've probably seen in a word

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processor before to tab things out which
is a way of sort of organizing things

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in a certain position.

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So basically,
the point is that the backslash character

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is actually interpreted
specifically by Python.

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And then depending on the character
that is typed after that backslash, and

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then it performs a special
function in that stream.

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So that's your sort of slash end,

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the first one, it cause it goes to the
start of a new line, and then the slash t

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cause it to tab to the next tab position
before I started the printing again.

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You can also use that to escape
special characters such as quote and

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double quotes, and that's useful if you've
got a string containing both characters.

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And probably the example would be
the best thing to show you there.

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I'll comment that out again.

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So I come down here and I'll type

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print ("The pet shop owner said "No,

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no, \'e\'s").

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You'll probably recognize this
if you're a Monty Python fan.

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I'll just close this down so
I can see this a bit better.

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That should have actually been a single
quote at the start and not a double.

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So what we are doing, is we are saying
that we are using both single quotes and

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double quotes in a particular string
which you may wanna use some time.

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Bearing in mind that we started off with
this string by saying it's a single quote.

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But by putting the backslash in front of
the quote you wanna use, that actually

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tells the string, or tells Python, to
treat it not as a special command to close

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the string in this case, but to set the
string that can actually be printed out.

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And you can also do something
conversely like this as well,

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which will give you the same results.

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Pet shop owner.

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Said,

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Like that.

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So if we actually run that now so
you can see what I mean.

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And you can see what we've done there,
and basically got the same result.

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But how we've used the start and
the end quotes and

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the slashes has caused the screen to
actually print out in the same way.

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So in the first example what the pet
owner said was in double quotes but

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his statement includes apostrophes so
we had to escape one or the other.

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And that's actually what
we did in those examples.

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So in this case the first method, the
first part of this was actually the third.

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If there's print statement in other words.

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For no other reason other than the fact
that if you type in two consecutive quotes

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either a single one or a double one,
IntelliJ will type a third one for you.

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Now, you might be wondering why would
you actually want to actually use three

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consecutive quotes, well this is actually
a feature of Python, and what it does,

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it's actually provided by Python to make
strings that spanned lines more readable.

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So, in other words, the string that we
split over several lines earlier is not

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easy to read because
of the embedded slash.

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And as you saw Python allows a string to
be split over several lines without doing

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that by using triple quotes, and the way
to do that, we type something like this.

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AnotherSplitString = """ This

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string has been split
over several lines""".

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There's the three quotes, and my typing.

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Okay, so that's actually a way to
actually create the string, and

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without having to use any backslashes.

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So, in other words, you wanna lay
out a string with breaks, but

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you don't want every line to
start a new line with printed,

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you can escape the end of
the line with slash dot as well.

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Let's see what that looks like so
print another string, anotherSplitString.

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Now, if I run that, this string
has been split over several lines.

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I can see it has done the equivalent
function to the slash

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ns that we were using earlier.

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The other thing you can do is, if you
wanna lay out a string with lots of breaks

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but you don't want everyone to
start a new line when printed,

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what you can do is escape the end
of the line with a slash dot.

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So experiment adding a backslash to the
end of the lines to see what happens when

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you run the program.

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And getting back to
the Monty Python example again,

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we can actually also do
something like this.

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We can type using the triple quotes,

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we can do (' ' ' The pet
shop owner said "No,

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no, 'e's' uh,...he's resting" ' ' ').

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Like so, which is another way of doing it.

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So you can see that the triple quote
feature is actually quite handy.

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And conversely we could
do something like this.

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We can just copy that and paste it.

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I could change the single
quotes there to double quotes.

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Like so, and again if you run that,
we get the same result, so

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that can be quite handy to look
at using those triple quotes.

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The other thing I just wanna point out is
in the case where you've got a quote and

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you're gonna go to have
four quotes in a row.

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That doesn't work too well, and

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you actually find that Python gets itself
into a little bit of a knot with that.

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So if you are using the three quotes,
you need to actually have a space before

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to make sure you haven't
got four quotes in a row,

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which actually [LAUGH] again you saw
that Python doesn't handle too well.

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So that serves as a basic introduction.

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And look it's only a basic introduction.

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What we're gonna do next,
is we're going to the next video.

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We're gonna start talking about variables.

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Because we sorta glossed over that
a little bit when you talked about,

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very basically what they are.

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But we're gonna actually talk about that
more in detail, what variables are, and

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how to use them.

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So we'll start that in the next video.