updated code

Author: callicoder

15-sorting/custom-sorting-struct.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+)
+
+type User struct {
+	Name string
+	Age  int
+}
+
+type UsersByAge []User
+
+func (u UsersByAge) Len() int {
+	return len(u)
+}
+func (u UsersByAge) Swap(i, j int) {
+	u[i], u[j] = u[j], u[i]
+}
+func (u UsersByAge) Less(i, j int) bool {
+	return u[i].Age < u[j].Age
+}
+
+func main() {
+	users := []User{
+		{
+			Name: "Rajeev",
+			Age:  28,
+		},
+		{
+			Name: "Monica",
+			Age:  31,
+		},
+		{
+			Name: "John",
+			Age:  56,
+		},
+		{
+			Name: "Amanda",
+			Age:  16,
+		},
+		{
+			Name: "Steven",
+			Age:  28,
+		},
+	}
+
+	// Sorting a slice of users by age
+	sort.Sort(UsersByAge(users))
+	fmt.Println("Sorted users by age: ", users)
+
+	// Sorting a slice of strings in the reverse order of length
+	sort.Stable(UsersByAge(users))
+	fmt.Println("[Stable] Sorted users by age: ", users)
+
+}

15-sorting/reverse-sorting.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+)
+
+func main() {
+	// Sorting a slice of Strings
+	strs := []string{"quick", "brown", "fox", "jumpes"}
+	sort.Sort(sort.Reverse(sort.StringSlice(strs)))
+	fmt.Println("Sorted strings in reverse order: ", strs)
+
+	// Sorting a slice of Integers
+	ints := []int{56, 19, 78, 67, 14, 25}
+	sort.Sort(sort.Reverse(sort.IntSlice(ints)))
+	fmt.Println("Sorted integers in reverse order: ", ints)
+
+	// Sorting a slice of Floats
+	floats := []float64{176.8, 19.5, 20.8, 57.4}
+	sort.Sort(sort.Reverse(sort.Float64Slice(floats)))
+	fmt.Println("Sorted floats in reverse order: ", floats)
+}

15-sorting/sorting-by-comparator.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+)
+
+func main() {
+	// Sorting a slice of strings by length
+	strs := []string{"United States", "India", "France", "United Kingdom", "Spain"}
+	sort.Slice(strs, func(i, j int) bool {
+		return len(strs[i]) < len(strs[j])
+	})
+	fmt.Println("Sorted strings by length: ", strs)
+
+	// Stable sort
+	sort.SliceStable(strs, func(i, j int) bool {
+		return len(strs[i]) < len(strs[j])
+	})
+	fmt.Println("[Stable] Sorted strings by length: ", strs)
+
+	// Sorting a slice of strings in the reverse order of length
+	sort.SliceStable(strs, func(i, j int) bool {
+		return len(strs[j]) < len(strs[i])
+	})
+	fmt.Println("[Stable] Sorted strings by reverse order of length: ", strs)
+}

15-sorting/sorting-struct-slice-by-comparator.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+)
+
+type User struct {
+	Name string
+	Age  int
+}
+
+func main() {
+	// Sorting a slice of structs by a field
+	users := []User{
+		{
+			Name: "Rajeev",
+			Age:  28,
+		},
+		{
+			Name: "Monica",
+			Age:  31,
+		},
+		{
+			Name: "John",
+			Age:  56,
+		},
+		{
+			Name: "Amanda",
+			Age:  16,
+		},
+		{
+			Name: "Steven",
+			Age:  28,
+		},
+	}
+
+	sort.Slice(users, func(i, j int) bool {
+		return users[i].Age < users[j].Age
+	})
+	fmt.Println("Sorted users by age: ", users)
+
+	// Stable sort
+	sort.SliceStable(users, func(i, j int) bool {
+		return users[i].Age < users[j].Age
+	})
+	fmt.Println("Sorted users by age: ", users)
+}

15-sorting/sorting.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+)
+
+func main() {
+	// Sorting a slice of Strings
+	strs := []string{"quick", "brown", "fox", "jumpes"}
+	sort.Strings(strs)
+	fmt.Println("Sorted strings: ", strs)
+
+	// Sorting a slice of Integers
+	ints := []int{56, 19, 78, 67, 14, 25}
+	sort.Ints(ints)
+	fmt.Println("Sorted integers: ", ints)
+
+	// Sorting a slice of Floats
+	floats := []float64{176.8, 19.5, 20.8, 57.4}
+	sort.Float64s(floats)
+	fmt.Println("Sorted floats: ", floats)
+}

16-command-line-flags/command-line-flags.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"strings"
+)
+
+type hobbies []string
+
+func (h *hobbies) String() string {
+	return fmt.Sprint(*h)
+}
+
+func (h *hobbies) Set(value string) error {
+	for _, hobby := range strings.Split(value, ",") {
+		*h = append(*h, hobby)
+	}
+	return nil
+}
+
+func main() {
+	// Declare a string flag called name with a default value ("Guest") and a help message
+	name := flag.String("name", "Guest", "specify your name")
+
+	// Declare a flag called age with default value of 0 and a help message
+	age := flag.Int("age", 0, "specify your age")
+
+	// Bind the command-line flag with an existing variable
+	var country string
+	flag.StringVar(&country, "country", "", "enter your country")
+
+	// Defining a custom flag
+	var hobbiesFlag hobbies
+	flag.Var(&hobbiesFlag, "hobbies", "comma separated list of hobbies")
+
+	// Enable command-line parsing
+	flag.Parse()
+
+	fmt.Printf("Hello %s\n", *name)
+	fmt.Printf("Your age is %d\n", *age)
+	fmt.Printf("Your are from %s\n", country)
+
+	fmt.Printf("Your hobbies are: ")
+	for _, hobby := range hobbiesFlag {
+		fmt.Printf("%s ", hobby)
+	}
+	fmt.Println()
+
+	// Read all the positional arguments
+	fmt.Println("Positional Arguments:", flag.Args())
+
+	// Read the i'th positional argument
+	i := 0
+	fmt.Printf("Positional argument at index %d: %v\n", i, flag.Arg(i))
+}

16-command-line-flags/positional-arguments.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+)
+
+func main() {
+	s := flag.Int("s", 0, "start line number")
+    t := flag.Int("t", 0, "end line number")
+
+	// Enable command-line parsing
+	flag.Parse()
+
+	fmt.Printf("Search file from line number %d to %d\n", *s, *t)
+
+    // Read all the positional arguments
+	fmt.Println("for keywords:", flag.Args())
+
+    // Read the i'th positional argument
+	i := 0
+	fmt.Printf("The keyword at index %d: %v\n", i, flag.Arg(i))
+}

17-url-encoding-decoding/01-url-encode/main.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	"fmt"
+	"net/url"
+)
+
+func main() {
+	// QueryEscape: Escape a string to safely place it inside a URL query string
+	str := "Gol@ng?&"
+	encodedStr := url.QueryEscape(str)
+
+	fmt.Println(encodedStr)
+
+	// PathEscape: Escape a string to safely place it inside a URL path segment
+	pathVar := "Gol@ng?&"
+	encodedPathVar := url.PathEscape(pathVar)
+	fmt.Println(encodedPathVar)
+}

17-url-encoding-decoding/02-url-decode/main.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"fmt"
+	"net/url"
+)
+
+func main() {
+	// QueryUnescape: Decode a URL query string
+	encodedStr := "Gol%40ng%3F%26"
+	decodedStr, err := url.QueryUnescape(encodedStr)
+	if err != nil {
+		fmt.Printf("Error decoding the string %v", err)
+	}
+
+	fmt.Println(decodedStr)
+
+	// PathUnescape: Decode a URL path segment
+	encodedPathVar := "Gol@ng%3F&"
+	decodedPathVar, err := url.PathUnescape(encodedPathVar)
+	if err != nil {
+		fmt.Printf("Error decoding the string %v", err)
+	}
+	fmt.Println(decodedPathVar)
+}

18-base64-encoding-decoding/01-base64-encoding/main.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"encoding/base64"
+	"fmt"
+)
+
+func main() {
+	data := "Gol@ng is Awesome?~"
+
+	// Standard Base64 Encoding
+	encodedData := base64.StdEncoding.EncodeToString([]byte(data))
+	fmt.Println(encodedData)
+
+	// Standard Base64 Encoding without padding
+	encodedDataWithoutPadding := base64.RawStdEncoding.EncodeToString([]byte(data))
+	fmt.Println(encodedDataWithoutPadding)
+
+	// URL and filename-safe Base64 encoding
+	urlSafeEncodedData := base64.URLEncoding.EncodeToString([]byte(data))
+	fmt.Println(urlSafeEncodedData)
+
+	// URL and filename-safe Base64 encoding without padding
+	urlSafeEncodedDataWithoutPadding := base64.RawURLEncoding.EncodeToString([]byte(data))
+	fmt.Println(urlSafeEncodedDataWithoutPadding)
+
+}