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Escape Sequences

2:58 with Jay McGavren

Sometimes, we need characters in a string that are hard to represent in program code. Escape sequences can help.

Before we move on from strings, we should take a moment to look at something called escape sequences. We won't be using these in the cat food store, but you'll definitely need to use them in other programs.

  • Sometimes, we need characters in a string that are hard to represent in program code.
  • The first line of code is supposed to print a string that includes a newline character, but we get a "Newline in constant" error when we try to run the code.
  • We want the "new paragraph" line to include a tab character to indent some text, but when I pressed the Tab key, my editor inserted space characters instead.
  • And we're getting more errors from the line that includes a quotation. It's supposed to be a single string that contains double quote marks, but what we wind up with is a a string containing "He said, ", code referring to a nonexistent value named Whoa, and a second, empty string at the end.
    static void Main(string[] args)
    {
        Console.WriteLine("first line
second line");
        Console.WriteLine("  new paragraph");
        Console.WriteLine("He said, "Whoa."");
    }

Escape sequences let you include characters in strings that might otherwise be hard to represent in code.

Newline: \n

skips to a
new line

Tab: \t

    Indents text

Double-quotes: \"

Inserts "double quotes"

Backslash: \\

Inserts a \ backslash
  • Let's update the previous program to use escape sequences for the hard-to-represent characters.
    static void Main(string[] args)
    {
        Console.WriteLine("first line\nsecond line");
        Console.WriteLine("\tnew paragraph");
        Console.WriteLine("He said, \"Whoa.\"");
        Console.WriteLine("A backslash: \\");
    }
  • 0:00

    Before we move on from strings,

  • 0:02

    we should take a moment to look at something called escape sequences.

  • 0:06

    We won't be using these in the cat food store.

  • 0:08

    But you'll definitely need to use them in other programs.

  • 0:11

    Sometimes we need characters in the string that are hard to represent

  • 0:14

    in program code.

  • 0:16

    This first line of code is supposed to pull a string that includes a new line

  • 0:19

    character.

  • 0:20

    But we get a new line and constant error when we to run the code.

  • 0:25

    We want the new paragraph line to include a Tab character to indent some text.

  • 0:29

    But when I press the Tab key, my editor inserted space characters instead, and

  • 0:35

    we're getting more errors from the line that includes a quotation.

  • 0:38

    It's supposed to be a single string that contains double quote marks.

  • 0:42

    But what we wind up with is a string containing He said, code referring

  • 0:46

    to a non existent value named Whoa, and a second empty string at the end.

  • 0:51

    Escape sequences allow you to include hard to represent characters within your

  • 0:55

    strings.

  • 0:56

    They usually consist of a backslash followed by another character.

  • 1:00

    To represent a newline character, you can type \n within a string.

  • 1:05

    To represent a tab, you can type \t.

  • 1:08

    To represent double quotes, you can type \" character.

  • 1:14

    And if you want to represent a backslash, type \\.

  • 1:19

    Let's update this program to use escape sequences for

  • 1:22

    the hard to represent characters.

  • 1:24

    I'll take the new line within this first line and

  • 1:27

    replace it with \n to represent a new line character.

  • 1:31

    I'll take these two spaces that are supposed to represent a tab and

  • 1:34

    replace it with \t so we get an actual tab character.

  • 1:38

    And I'll put backslashes before both of the extra quote characters so

  • 1:42

    that we can have quotation marks within our quoted string.

  • 1:46

    Finally, let's add one extra line that prints a backslash character.

  • 1:50

    We do that with a double backslash within our quoted string.

  • 1:54

    Now let's try running this and see if our syntax errors go away.

  • 2:01

    I'll hit the up arrow to bring up our dotnet run command and hit Enter, and

  • 2:05

    this time everything works.

  • 2:08

    Our first line of code results in the string first line being printed,

  • 2:13

    followed by a new line, followed by the text's second line.

  • 2:16

    Our second line of code results in a Tab character being printed,

  • 2:19

    followed by our text.

  • 2:21

    We have our quotation marks included in the output by our third line of code.

  • 2:27

    And in our fourth line of code,

  • 2:28

    the double backslash within the string gets replaced with a single backslash.

  • 2:32

    You've learned all the basics of working with strings in C#.

  • 2:35

    You can append strings to other strings by concatenating them.

  • 2:39

    You can embed data within strings using interpolation.

  • 2:42

    And you can embed special characters using Escape sequences.

  • 2:46

    Up next, our cat food store needs to take the number of cans the user entered and

  • 2:50

    calculate the total cost.

  • 2:52

    That's going to require working with numbers in math.

  • 2:55

    We'll look at both of those topics in the next stage.

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