maps

about_maps.go

@@ -0,0 +1,31 @@
+package go_koans
+
+func testMaps() {
+  ages := map[string]int{
+    "bob": 10,
+    "joe": 20,
+    "dan": 30,
+  }
+
+  age := ages["bob"]
+  assert(age == __int__) // map syntax is warmly familiar
+
+  age, ok := ages["bob"]
+  assert(ok == __bool__) // with a handy addition for presence checking
+
+  age, ok = ages["steven"]
+  assert(age == __int__) // the zero value is used when absent
+  assert(__bool__) // though there are better ways to check for presence
+
+  assert(len(ages) == __int__) // length is based on keys
+
+  ages["bob"] = 99
+  assert(ages["bob"] == __int__) // values can be changed for keys
+
+  ages["steven"] = 77
+  assert(ages[__string__] == 77) // new ones can be added
+
+  delete(ages, "steven")
+  age, ok = ages["steven"]
+  assert(__bool__) // key/value pairs can be removed
+}

setup_koans_test.go

@@ -26,10 +26,10 @@ func TestKoans(t *testing.T) {
   //testAnonymousFunctions()
   //testVariadicFunctions()
   //testFiles()
-  testInterfaces()
+  //testInterfaces()
+  testMaps()
 
   // TODO: ie, gameplan
-  //testMaps()
   //testStructs()
   //testAllocation()
   //testPointers()