add: exercises and quiz for appending and slicing

16-slices/exercises/15-slicing-housing-prices/main.go

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+package main
+
+// ---------------------------------------------------------
+// EXERCISE: Slicing the Housing Prices
+//
+//  We have received housing prices. Your task is to print only the requested
+//  columns of data (see the expected output).
+//
+//  1. Separate the data by the newline ("\n") -> rows
+//
+//  2. Separate each row of the data by the separator (",") -> columns
+//
+//  3. Find the from and to positions inside the columns depending
+//     on the command-line arguments.
+//
+//  4. Print only the requested column headers and their data
+//
+//
+// RESTRICTIONS
+//
+//  + You should use slicing when printing the columns.
+//
+//
+// EXPECTED OUTPUT
+//
+//  go run main.go
+//    Location       Size           Beds           Baths          Price
+//
+//    New York       100            2              1              100000
+//    New York       150            3              2              200000
+//    Paris          200            4              3              400000
+//    Istanbul       500            10             5              1000000
+//
+//
+//  go run main.go Location
+//    Location       Size           Beds           Baths          Price
+//
+//    New York       100            2              1              100000
+//    New York       150            3              2              200000
+//    Paris          200            4              3              400000
+//    Istanbul       500            10             5              1000000
+//
+//
+//  NOTE : Finds the position of the Size column and slices the columns
+//         appropriately.
+//
+//  go run main.go Size
+//    Size           Beds           Baths          Price
+//
+//    100            2              1              100000
+//    150            3              2              200000
+//    200            4              3              400000
+//    500            10             5              1000000
+//
+//
+//  NOTE : Finds the positions of the Size and Baths columns and
+//         slices the columns appropriately.
+//
+//  go run main.go Size Baths
+//    Size           Beds           Baths
+//
+//    100            2              1
+//    150            3              2
+//    200            4              3
+//    500            10             5
+//
+//
+//  go run main.go Beds Price
+//    Beds           Baths          Price
+//
+//    2              1              100000
+//    3              2              200000
+//    4              3              400000
+//    10             5              1000000
+//
+//
+//  Note : It works even if the given column name does not exist.
+//
+//  go run main.go Beds NotExist
+//    Beds           Baths          Price
+//
+//    2              1              100000
+//    3              2              200000
+//    4              3              400000
+//    10             5              1000000
+//
+//
+//  go run main.go NotExist NotExist
+//    Location       Size           Beds           Baths          Price
+//
+//    New York       100            2              1              100000
+//    New York       150            3              2              200000
+//    Paris          200            4              3              400000
+//    Istanbul       500            10             5              1000000
+//
+//
+// HINTS
+//
+//  + strings.Split function can separate a string into a []string
+//
+// ---------------------------------------------------------
+
+func main() {
+	const (
+		data = `Location,Size,Beds,Baths,Price
+New York,100,2,1,100000
+New York,150,3,2,200000
+Paris,200,4,3,400000
+Istanbul,500,10,5,1000000`
+
+		separator = ","
+	)
+}

16-slices/exercises/15-slicing-housing-prices/solution/main.go

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+// 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"
+	"os"
+	"strings"
+)
+
+func main() {
+	const (
+		data = `Location,Size,Beds,Baths,Price
+New York,100,2,1,100000
+New York,150,3,2,200000
+Paris,200,4,3,400000
+Istanbul,500,10,5,1000000`
+
+		separator = ","
+	)
+
+	// parse the data
+	rows := strings.Split(data, "\n")
+	cols := strings.Split(rows[0], separator)
+
+	// default case: slice for all the columns
+	from, to := 0, len(cols)
+
+	// find the from and to positions depending on the command-line arguments
+	args := os.Args[1:]
+	for i, v := range cols {
+		l := len(args)
+
+		if l >= 1 && v == args[0] {
+			from = i
+		}
+
+		if l == 2 && v == args[1] {
+			to = i + 1 // +1 because the stopping index is a position
+		}
+	}
+
+	for i, row := range rows {
+		cols := strings.Split(row, separator)
+
+		// print the only the requested columns
+		for _, h := range cols[from:to] {
+			fmt.Printf("%-15s", h)
+		}
+		fmt.Println()
+
+		// print extra new line for the header
+		if i == 0 {
+			fmt.Println()
+		}
+	}
+}