Hello world
# hello.exs
defmodule Greeter do
def greet(name) do
message = "Hello, " <> name <> "!"
IO.puts message
end
end
Greeter.greet("world")
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elixir hello.exs
# Hello, world!
Pattern matching
user = %{name: "Tom", age: 23}
%{name: username} = user
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This sets username to "Tom".
If
if false do
"This will never be seen"
else
"This will"
end
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Types (Primitives)
nil |
Nil/null |
true / false |
Boolean |
?a |
Integer (ASCII) |
23 |
Integer |
3.14 |
Float |
'hello' |
Charlist |
<<2, 3>> |
Binary |
"hello" |
Binary string |
:hello |
Atom |
[a, b] |
List |
{a, b} |
Tuple |
%{a: "hello"} |
Map |
%MyStruct{a: "hello"} |
Struct |
fn -> ... end |
Function |
Modules (Importing)
require Redux # compiles a module
import Redux # compiles, and you can use without the Redux.
prefix
use Redux # compiles, and runs Redux.__using__/1
use Redux, async: true
import Redux, only: [duplicate: 2]
import Redux, only: :functions
import Redux, only: :macros
import Foo.{Bar, Baz} |
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Maps
user = %{
name: "John",
city: "Melbourne"
}
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IO.puts "Hello, " <> user.name
Pattern matching in functions
ef greet(%{name: username}) do
IO.puts "Hello, " <> username
end
user = %{name: "Tom", age: 23}
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Pattern matching works in function parameters too.
Case
case {1, 2, 3} do
{4, 5, 6} ->
"This clause won't match"
{1, x, 3} ->
"This will match and bind x to 2"
_ ->
"This will match any value"
end
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With
case Users.create_user(attrs) do
{:ok, user} -> ...
{:error, changeset} -> ...
end
with {:ok, user} <- Users.create_user(attrs) do
...
else
{:error, changeset} -> ...
end
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Lists
users = [ "Tom", "Dick", "Harry" ]
Enum.map(users, fn user ->
IO.puts "Hello " <> user
end)
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Piping
source
|> transform(:hello)
|> print()
# Same as:
print(transform(source, :hello))
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These two are equivalent.
Cond
cond do
1 + 1 == 3 ->
"I will never be seen"
2 * 5 == 12 ->
"Me neither"
true ->
"But I will (this is essentially an else)"
end
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Errors
try do
throw(:hello)
catch
message -> "Got #{message}."
after
IO.puts("I'm the after clause.")
end
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Type checks
is_atom/1 |
is_binary/1 |
is_nil/1 |
is_bitstring/1 |
is_list/1 |
is_number/1 |
is_boolean/1 |
is_map/1 |
is_pid/1 |
is_function/1 |
is_tuple/1 |
is_port/1 |
is_function/2 |
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is_reference/1 |
is_integer/1 |
is_float/1 |
Operators
left != right # equal
left !== right # match
left ++ right # concat lists
left <> right # concat string/binary
left =~ right # regexp |
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