Heads up! To view this whole video, sign in with your Courses account or enroll in your free 7-day trial. Sign In Enroll
Preview
Start a free Courses trial
to watch this video
Sometimes, we need characters in a string that are hard to represent in program code.
Escape sequences are used to represent characters that would normally be difficult to include in program code.
Newline: \n
skips to a
new line
Tab: \t
Indents text
Double-quotes: \"
Inserts "double quotes"
Single-quote: \'
Inserts 'single quotes'
Backslash: \\
Inserts a \ backslash
Here's some code that uses escape sequences:
puts "first line\nsecond line"
puts "\tindented text"
puts "He said, \"Whoa.\""
Output:
first line
second line
indented text
He said, "Whoa."
You don't always have to escape quotation marks in your strings:
puts "Double-quoted strings can hold single quotes: ''"
puts 'Single-quoted strings can hold double quotes: ""'
# But...
puts "Double-quotes in double-quoted strings need to be \"escaped\"."
puts 'Single-quotes in single-quoted strings need to be \'escaped\'.'
Additional practice
We've created a workshop where you can get additional practice with Ruby strings. Don't miss this chance to strengthen your skills!
Visit the workshop here: Practice Strings in Ruby
Sometimes, we need characters
in a string that are hard to
0:00
represent in program code.
0:02
The first line of code prints a string
that includes a newline character.
0:05
But it's awkward to read,
0:08
with the second half of the string
starting on the second line.
0:10
We want line 3 to include a tab
character to indent some text, but
0:14
when I press the tab key, my editor
inserted space characters, instead.
0:18
And line 4 isn't even valid Ruby code.
0:22
It's supposed to be a single string
that contains double quote marks.
0:25
But what we wind up with is a string
containing he said, some invalid Ruby code
0:28
referring to a non-existent object named
Whoa, and a second string, which is empty.
0:34
To address this problem,
Ruby offers escape sequences.
0:41
An escape sequence is a portion of
a string that represents a character that
0:46
would normally be hard to
represent in program code.
0:50
Each of these two character
combinations you see here
0:53
actually represents a single character.
0:56
So \ followed by n, represents a new line
character, which skips to a new line.
0:59
\ followed by t, represents a tab
character, which indents text.
1:05
\ followed by a " character inserts double
quotes, even into a double quoted string.
1:10
\ followed by a ' character
inserts single quotes,
1:16
again, even into a single quoted string.
1:20
And because you're going to need a way to
insert backslash characters without Ruby
1:22
thinking you're starting
an escape sequence,
1:26
\\ inserts a single backslash character.
1:28
Let's update the previous program
to use escape sequences for
1:33
the hard to represent characters.
1:37
So first, let's take the new line
character that's in the middle of this
1:39
first line and replace it with \n to
represent an actual new line character.
1:42
Let's take the two spaces here on
the second line and replace it
1:48
with \t which represents a tab character,
that should indent the text for us.
1:51
And let's take the double quote
characters that Ruby is mistaking for
1:57
the end of a string, and
escape those using backslashes as well.
2:00
So that all of this
becomes a single string.
2:04
Let's save that, and try rerunning it.
2:07
And everything works.
2:12
Our \n here on the first line,
2:13
gets replaced with a new
line character down below.
2:16
\t gets replaced with a tab character.
2:18
And our \" get replaced with
actual quotation marks.
2:22
Just so you know, you don't always have to
escape quotation marks into your strings.
2:28
Double quoted strings can hold
single quotes without escaping them.
2:33
Single quoted strings can hold
double quotes without escaping them.
2:36
But, double quote characters within
double quoted strings need to be escaped.
2:40
And so do single quotes
within single quoted strings.
2:44
So, now that we know
about escape sequences,
2:48
we know that the \n at the end of our
answer variable is a new line character.
2:50
When the user presses the enter key
to signal they're finished entering
2:56
an answer, it adds a new line
character on the end of the string,
2:59
which gets returned by gets.
3:03
To remove it, we'll need to call
a method on the string object,
3:06
which we'll learn how to
do in the next stage.
3:09
Knowing how to work with strings is
another essential programming skill,
3:12
one that's definitely worth practicing.
3:15
Be sure to check the teacher's notes
to learn ways to get more practice with
3:17
strings.
3:21
Now you've learned the basics
of working with strings in Ruby.
3:22
You can append strings to other
strings by concatenating them.
3:25
You can embed data within
strings using interpolation.
3:29
And you can embed special
characters using escape sequences.
3:32
But that's only a small fraction
of the features Ruby offers for
3:37
working with strings.
3:40
To do more, you're going to need to
know how to call methods directly on
3:41
the strings, and not just for strings.
3:45
Virtually everything in Ruby
has methods you can call on it.
3:48
We'll learn how to do
that in the next stage.
3:51
You need to sign up for Treehouse in order to download course files.
Sign up