48-string-functions.md

This Go code demonstrates various string manipulation functions from the strings package. Let's go through the code with inline comments and explanations:

// Importing necessary packages.
import (
	"fmt"
	s "strings" // Importing the strings package and aliasing it as 's'.
)

// Alias for fmt.Println for brevity.
var p = fmt.Println

// The main function, where the execution of the program begins.
func main() {
	// Using various string manipulation functions from the strings package.

	// Checking if a string contains a substring.
	p("Contains:  ", s.Contains("test", "es"))

	// Counting occurrences of a character in a string.
	p("Count:     ", s.Count("test", "t"))

	// Checking if a string has a specified prefix.
	p("HasPrefix: ", s.HasPrefix("test", "te"))

	// Checking if a string has a specified suffix.
	p("HasSuffix: ", s.HasSuffix("test", "st"))

	// Finding the index of the first occurrence of a substring in a string.
	p("Index:     ", s.Index("test", "e"))

	// Joining strings in a slice with a specified separator.
	p("Join:      ", s.Join([]string{"a", "b"}, "-"))

	// Repeating a string a specified number of times.
	p("Repeat:    ", s.Repeat("a", 5))

	// Replacing occurrences of a substring with another substring.
	p("Replace:   ", s.Replace("foo", "o", "0", -1))
	p("Replace:   ", s.Replace("foo", "o", "0", 1))

	// Splitting a string into a slice based on a specified separator.
	p("Split:     ", s.Split("a-b-c-d-e", "-"))

	// Converting a string to lowercase.
	p("ToLower:   ", s.ToLower("TEST"))

	// Converting a string to uppercase.
	p("ToUpper:   ", s.ToUpper("test"))
}

Output

Contains:   true
Count:      2
HasPrefix:  true
HasSuffix:  true
Index:      1
Join:       a-b
Repeat:     aaaaa
Replace:    f00
Replace:    f0o
Split:      [a b c d e]
ToLower:    test
ToUpper:    TEST

Explanation:

1. s.Contains("test", "es"):

   • Checks if the string "test" contains the substring "es."

2. s.Count("test", "t"):

   • Counts the occurrences of the character "t" in the string "test."

3. s.HasPrefix("test", "te"):

   • Checks if the string "test" has the prefix "te."

4. s.HasSuffix("test", "st"):

   • Checks if the string "test" has the suffix "st."

5. s.Index("test", "e"):

   • Finds the index of the first occurrence of the substring "e" in the string "test."

6. s.Join([]string{"a", "b"}, "-"):

   • Joins the strings "a" and "b" with the separator "-."

7. s.Repeat("a", 5):

   • Repeats the string "a" five times.

8. s.Replace("foo", "o", "0", -1):

   • Replaces all occurrences of the substring "o" with "0" in the string "foo."

9. s.Replace("foo", "o", "0", 1):

   • Replaces the first occurrence of the substring "o" with "0" in the string "foo."

10. s.Split("a-b-c-d-e", "-"):

    • Splits the string "a-b-c-d-e" into a slice based on the separator "-."

11. s.ToLower("TEST"):

    • Converts the string "TEST" to lowercase.

12. s.ToUpper("test"):

    • Converts the string "test" to uppercase.

These functions provide a wide range of string manipulation capabilities, making it convenient to work with strings in Go.