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Strings and Operators
7:17Let's explore Strings and how to concatenate them together
I like to imagine string just like a
banner you might see at a party with each
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letter strung together.
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That's really what a string is, right?
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It's a series of characters.
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The string data type provides some very
handy methods that I'd like you to get
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familiar with.
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After you create a string,
it cannot be changed.
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This is what is known as immutable or
impossible to modify.
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I'll remind you of this as we
look at some of these examples.
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Why don't we pop open a shell and
I can show you what I'm talking about.
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So, string literals, they can be made
with either single or double quotes.
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And I can imagine that you
might say something like this.
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You could say, 'I cannot understand
why you need two options for quotes'.
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Totally understand why you
might say something like that.
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But that's probably a little bit formal,
isn't it?
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We should probably use a conjunction.
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How about we say something like,
'I can't understand'.
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Oops, that's a problem, right?
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We've got a quote inside of the quote.
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We got a single quote, we are trying
to use a single quote, uh-oh.
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Now, option is that you
can actually make it so
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the quote is ignored by doing
something called escaping.
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So the backslash starts what is
known us an escape sequence.
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So the backslash, and
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then a quote, basically tells
the interpreter to treat that quote
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like a character instead of treating
it like part of the syntax, right?
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So if I do, can\ 't understand,
now it will see.
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But, I mean this is kinda ugly, isn't it?
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This backslash t.
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Are you glad there's two
types of quotes yet?
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And actually, look, the REPL fixed it.
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So you can use quotes like that.
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So if you use double quotes,
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then you could very easily use
the single quote inside of it, like so.
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Now we can say, "I can't", right?
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There's a nice string.
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And actually,
escape sequences are great for
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adding blank lines inside of your string.
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So there's a special one that you'll see.
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If we come over here and we go up,
let's get this I can't back here.
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Let's say "I can't..., and
then we wanna add a new line.
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And so that escape sequence to add
a new blank line is \n for new line.
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So we'd add two, two blank lines and
we'll say, I can't even.
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And the REPL here is playing tricks on us.
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It's trying really hard to keep
things on one line for us.
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But actually if you print that string; so
we'll go ahead and say we'll print.
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And then we'll get back the result
that was just there, right?
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So we use the underscore.
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So you'll see that it is actually
I can't new line new line even.
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There's our new lines.
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My wife says that to me all the time while
shaking her head about my dad jokes.
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You're not the only one.
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I suppose,
I should quote her though, right?
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So I would say, "She said,.
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[LAUGH] I can't, so now what?
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Now we've got a single quote and
a double quote in here.
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So actually, triple quotes
allow you to start the string.
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So we could say, """She said, "I can't...
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And the nice thing about triple
quotes is it allows you to have
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spaces in your string.
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So we can press like this and
see those triple dots over here.
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That means, it's waiting for me to,
it's waiting for those final three quotes.
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So we can say, "I can't...
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even.", so she said that.
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And still,
there's another quote there, right?
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So I'm ending that quote and then it's
waiting for three quotes to end it.
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So there we go, and if I say, go up
a couple times here, we say, print (_).
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She said "I can't...
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even.", that's what she said.
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All right, so
now that we got creation out of the way,
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let's look at combining
some strings together.
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What if I had a string like this word,
here, chocolate?
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Now we can actually combine it together
with another string using a plus sign.
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So I can say, "chocolate" + "marshmallow".
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And you'll see what it
returned was a brand new
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string with the two words pushed together.
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This is called concatenation.
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Now, it's important to remember when
you're concatenating strings to include
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the proper spacing.
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Otherwise, it will be
slammed together like this.
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So what we want is
probably more like this,
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"chocolate' + " and
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marshmallows".
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There we go, that feels good.
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And of course,
we can store that new string that
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was created in a variable, right?
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So, we could say desert =
"chocolate" + " and marshmallows".
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So that was a new string created and
then we labeled it with dessert.
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And we can use that variable
to create a brand new one.
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This is called reassigning.
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So as I dessert = dessert + " and
graham crackers".
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And now, that might look like
we changed the variable dessert.
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But what happened was that this statement,
dessert + " and
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graham crackers", created a new string.
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And we removed our already existing
label and put it on the new string.
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We reassigned it.
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The old string,
since it didn't have a label,
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is essentially thrown away,
like those leftovers in my office fridge.
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Remember, we didn't actually change the
original string because we can't, right?
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And that's because strings are immutable.
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This appending of more text to
the end of a string is pretty common.
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So there is a shortcut
called in-place addition.
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So if we say dessert, we can say +=.
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And basically,
that's just like the line above.
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It's saying dessert = dessert + and
then whatever we do.
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So we say += ", yum.
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And if we take a look, 'chocolate and
marshmallows and graham crackers, yum'.
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So [LAUGH] that needs some
exclamation points, am I right?
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And I want some more than just a couple.
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I don't wanna just add
a whole bunch of them myself.
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I'd rather do that in code.
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So that's where the asterisk
comes into play.
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So check this out.
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If I want to repeat the string, well,
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here's the string,
I can then do a * for multiplication.
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I say do that 20 times.
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Awesome.
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In addition to exclamations,
this is really handy for
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trying to draw layouts in text.
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So let's append those.
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So we'll say dessert, and
we'll do an in-place addition, so dessert,
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basically, that's desert +=,
and we'll say "!" * 20.
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And there we go.
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Now before I append some more
string information in your brain,
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let's take a quick break and
return to talk some more about strings.
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We'll talk about various handy
methods that a string provides.
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