publish arrays

examples.txt

@@ -6,7 +6,7 @@ Hello World
 # For
 # If/Else
 # Switch
-# Arrays
+Arrays
 # Slices
 Maps
 # Range

examples/arrays/arrays.go

@@ -1,10 +1,44 @@
+// In Go, an array is a numbered sequence of elements of a
+// specific length.
+
 package main
 
 import "fmt"
 
 func main() {
+
+    // The type of elements and length are both part of
+    // the array's type. Here we create an array `x` that
+    // will hold exactly 5 ints.
     var x [5]int
+
+    // By default an array is zero-valued, which for ints
+    // means an array of `0`s.
+    fmt.Println("emp:", x)
+
+    // We can set a value at a given index using the
+    // `array[index] = value` syntax, and get a value
+    // with `array[index]`.
     x[4] = 100
-    fmt.Println(x)
-    fmt.Println(x[4])
+    fmt.Println("set:", x)
+    fmt.Println("get:", x[4])
+
+    // Use this syntax to decalare and initalize an array
+    // in one line.
+    y := [5]int{1, 2, 3, 4, 4}
+    fmt.Println("dcl:", y)
+
+    // The builtin `len` returns the length of an array.
+    fmt.Println("len:", len(x))
+
+    // Array types are one-dimensional, but you can
+    // compose types to build multi-dimensional data
+    // structures.
+    var twoD [2][3]int
+    for i := 0; i < 2; i++ {
+        for j := 0; j < 3; j++ {
+            twoD[i][j] = i + j
+        }
+    }
+    fmt.Println("2d: ", twoD)
 }

examples/arrays/arrays.sh

@@ -0,0 +1,12 @@
+# Note that arrays appear in the form `[v1 v2 v3 ...]`
+# when printed with `fmt.Println`.
+$ go run arrays.go
+emp: [0 0 0 0 0]
+set: [0 0 0 0 100]
+get: 100
+dcl: [1 2 3 4 4]
+len: 5
+2d:  [[0 1 2] [1 2 3]]
+
+# You'll see _slices_ much more often than arrays in
+# typical Go code. We'll look at slices next.

examples/maps/maps.go

@@ -1,4 +1,4 @@
-// Maps are Go's built-in [associative data type](http://en.wikipedia.org/wiki/Associative_array)
+// _Maps_ are Go's built-in [associative data type](http://en.wikipedia.org/wiki/Associative_array)
 // (sometimes called _hashes_ or _dicts_ in other languages).
 
 package main