Strings

Mix.install([
  {:kino, github: "livebook-dev/kino", override: true},
  {:kino_lab, "~> 0.1.0-dev", github: "jonatanklosko/kino_lab"},
  {:vega_lite, "~> 0.1.4"},
  {:kino_vega_lite, "~> 0.1.1"},
  {:benchee, "~> 0.1"},
  {:ecto, "~> 3.7"},
  {:math, "~> 0.7.0"},
  {:faker, "~> 0.17.0"},
  {:utils, path: "#{__DIR__}/../utils"}
])

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Setup

Ensure you type the ea keyboard shortcut to evaluate all Elixir cells before starting. Alternatively you can evaluate the Elixir cells as you read.

Strings

A string is any sequence of characters contained within two double quotes "". A character is any single number, letter, or symbol.

"T" # letters
"t" # letters
"1" # numbers
"1.2" # numbers
"&" # symbols
"_" # symbols

You can visualize a string as characters joined together by strings. Strings can be a single character, no characters, or many characters!

flowchart LR
  S --- T --- R --- I --- N --- G

Strings can contain single quotes and other symbols such as !@#$%^&*()_+-=';: and more.

"!@#$%^&*()_+-=';:"

They are useful for representing all kinds of information as text.

Your Turn

In the Elixir cell below, create a string "Hello, world!". This is a rite of passage for every programmer.

String Operators

String operators allow us to manipulate strings.

The <> operator joins two strings together. Joining strings together is called string concatenation.

"hello, " <> "world."

Only strings can be concatenated together using the <> operator. You’ll notice concatenating 1 causes an error expected binary argument in <> operator but got 1

"hello" <> 1

Your Turn

In the Elixir cell below, use string concatenation to join "Hi, " and the name of one of your classmates.

So "Peter" would be come "Hi, Peter.".

Replace nil with your answer.

answer = nil

Utils.feedback(:string_concatenation, answer)

String Interpolation

Using #{}, We can also interpolate values in strings. Essentially, this means we can evaluate code inside of a string. The code you want to interpolate inside of the string goes between the curly braces {}.

So we can evaluate 4 + 4, which equals 8 inside a string.

"I have #{4 + 4} apples."

String interpolation is often useful when your string has many computed values or tricky punctuation. Otherwise, it’s easy to make mistakes.

Notice that there’s a grammar mistake below that could easily be missed when using string concatenation.

"I have" <> "8" <> "apples"

Your Turn

In the Elixir cell below, use string interpolation to say I have #{X - 1} classmates.. Where X is the number of people in your cohort including yourself.

Replace nil with your answer.

answer = nil

Utils.feedback(:string_interpolation, answer)

Commit Your Progress

Run the following in your command line from the project folder to track and save your progress in a Git commit.

$ git add .
$ git commit -m "finish strings section"