Cheatsheet

diff --git a/sandbox.exs b/sandbox.exs
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+IO.inspect [1, 2, true, "abc"] ++ [3, 2, "abc"] # Concatenate two lists.
+IO.inspect [1, 2, true, "abc"] -- [3, 2, "abc"] # List subtraction.
+IO.inspect(hd [1, 2, 3]) # Head of a list.
+IO.inspect(tl [1, 2, 3]) # Tail of a list.
+
+tuple = {:ok, "hello"}
+IO.inspect(elem tuple, 1) # Get the second element of a tuple.
+
+IO.inspect "ABC" <> "XYZ" # String concatenation.
+
+l = [1, 2, 3]
+[h | t] = l
+IO.inspect {h, t}
+IO.inspect [0 | l]
+a = 2
+{^a, b} = {2, 42} # Pin operator.
+IO.inspect b, label: "b"
+{x, x} = {10, 10} # 'x' must be bind to the same value.
+IO.inspect x, label: "x"
+
+str = "hëllö" <> <<0>> # Append a zero to the string (binary).
+IO.inspect str, binaries: :as_binaries
+
+IO.inspect(<<3::4>> === <<0::1, 0::1, 1::1, 1::1>>) # Same binaries: 3 encoded on 4 bits.
+IO.inspect(is_binary <<0xFF, 0x5A>>) # true.
+IO.inspect(is_binary <<0xFF, 0xF::4>>) # false: binaries must be on a multiple of 8 bits.
+IO.inspect(is_bitstring <<0xFF, 0xF::4>>) # true.
+
+# Pattern matching on binaries.
+<<x::utf8, rest::binary>> = "über"
+IO.inspect(x === ?ü) # true.
+
+# 'charlist': the string in Erlang.
+IO.inspect('hëllò', charlists: :as_lists)
+IO.inspect(to_string('hëllò') == "hëllò") # true.
+IO.inspect('hëllò' == to_charlist("hëllò")) # true.
+
+# keyword list.
+IO.inspect([{:a, 1}, {:b, 2}] === [a: 1, b: 2]) # true.
+IO.inspect(a: 1, b: 2, c: 3) # Brackets omitted.
+
+# Maps.
+map = %{:a => 1, 2 => :b}
+IO.inspect map[:a] # Print 1.
+IO.inspect map.a # Special syntax with atom key, print 1.
+IO.inspect map[2] # Print ':b'.
+IO.inspect map[3] # Print 'nil'.
+%{:a => a} = map
+IO.inspect a # Print 1.
+IO.inspect %{map | 2 => "two"} # Updating 'map'.
+
+# Module.
+defmodule Math do
+    def sum(a, b) do
+        a + b
+    end
+end
+
+IO.inspect Math.sum(1, 2)
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