add: exercises and quiz for appending and slicing

16-slices/exercises/12-housing-prices-averages/solution/main.go

@@ -0,0 +1,104 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	const (
+		header = "Location,Size,Beds,Baths,Price"
+		data   = `New York,100,2,1,100000
+New York,150,3,2,200000
+Paris,200,4,3,400000
+Istanbul,500,10,5,1000000`
+
+		separator = ","
+	)
+
+	var (
+		locs                       []string
+		sizes, beds, baths, prices []int
+	)
+
+	rows := strings.Split(data, "\n")
+
+	for _, row := range rows {
+		cols := strings.Split(row, separator)
+
+		locs = append(locs, cols[0])
+
+		n, _ := strconv.Atoi(cols[1])
+		sizes = append(sizes, n)
+
+		n, _ = strconv.Atoi(cols[2])
+		beds = append(beds, n)
+
+		n, _ = strconv.Atoi(cols[3])
+		baths = append(baths, n)
+
+		n, _ = strconv.Atoi(cols[4])
+		prices = append(prices, n)
+	}
+
+	for _, h := range strings.Split(header, separator) {
+		fmt.Printf("%-15s", h)
+	}
+	fmt.Printf("\n%s\n", strings.Repeat("=", 75))
+
+	for i := range rows {
+		fmt.Printf("%-15s", locs[i])
+		fmt.Printf("%-15d", sizes[i])
+		fmt.Printf("%-15d", beds[i])
+		fmt.Printf("%-15d", baths[i])
+		fmt.Printf("%-15d", prices[i])
+		fmt.Println()
+	}
+
+	// -------------------------------------------------------------------------
+	// print the averages
+	//
+	// evil note:
+	// later on, you will see how easy it would be to solve this
+	// using the functions instead. there are a lot of repetitive code here.
+	// -------------------------------------------------------------------------
+	fmt.Printf("\n%s\n", strings.Repeat("=", 75))
+
+	// jump over the location column
+	fmt.Printf("%-15s", "")
+
+	var sum int
+
+	for _, n := range sizes {
+		sum += n
+	}
+	fmt.Printf("%-15.2f", float64(sum)/float64(len(sizes)))
+
+	sum = 0
+	for _, n := range beds {
+		sum += n
+	}
+	fmt.Printf("%-15.2f", float64(sum)/float64(len(beds)))
+
+	sum = 0
+	for _, n := range baths {
+		sum += n
+	}
+	fmt.Printf("%-15.2f", float64(sum)/float64(len(baths)))
+
+	sum = 0
+	for _, n := range prices {
+		sum += n
+	}
+	fmt.Printf("%-15.2f", float64(sum)/float64(len(prices)))
+
+	fmt.Println()
+}