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Go fmt.Sprintf String Formatting

In Go, you can use fmt.Sprintf to format strings, following this format:

fmt.Sprintf(format pattern, argument list...)

Format Pattern: A string pattern where format specifiers start with %, such as %s for string format and %d for decimal integer format.
Argument List: Multiple arguments separated by commas, which must correspond in number to the specifiers in the format pattern, otherwise, an error will occur at runtime.

Example

package main

import (
    "fmt"
    "io"
    "os"
)

func main() {
    // Formatting a string in Go and assigning it to a new string using fmt.Sprintf
    // %s represents a string
    var stockcode = "000987"
    var enddate = "2020-12-31"
    var url = "Code=%s&endDate=%s"
    var target_url = fmt.Sprintf(url, stockcode, enddate)
    fmt.Println(target_url)

    // Another example, %d represents an integer
    const name, age = "Kim", 22
    s := fmt.Sprintf("%s is %d years old.\n", name, age)
    io.WriteString(os.Stdout, s) // For simplicity, ignoring some errors
}

Output:

Code=000987&endDate=2020-12-31
Kim is 22 years old.

Example

package main
import (
    "fmt"
    "io"
    "os"
)
func main() {

    // Declaring numeric variables
    const num1, num2, num3 = 5, 10, 15

    // Calling the Sprintf() function
    s := fmt.Sprintf("%d + %d = %d", num1, num2, num3)

    // Using the WriteString() function to output the result to the terminal
    io.WriteString(os.Stdout, s)

}

Output:

5 + 10 = 15

Go String Format Specifiers:

Format	Description
%v	Default format for the value
%+v	Adds field names to the default format
%#v	A Go-syntax representation of the value
%T	A Go-syntax representation of the type of the value
%%	A literal percent sign
%b	Binary representation for integers
%o	Octal representation for integers
%d	Decimal representation for integers
%x	Hexadecimal representation for integers
%X	Hexadecimal representation with uppercase letters for integers
%U	Unicode format
%f	Floating-point number
%p	Pointer representation in hexadecimal

Example

package main

import (
    "fmt"
    "os"
)

type point struct {
    x, y int
}

func main() {

    p := point{1, 2}
    fmt.Printf("%v\n", p)

    fmt.Printf("%+v\n", p)

    fmt.Printf("%#v\n", p)

    fmt.Printf("%T\n", p)

    fmt.Printf("%t\n", true)

    fmt.Printf("%d\n", 123)

    fmt.Printf("%b\n", 14)

    fmt.Printf("%c\n", 33)

    fmt.Printf("%x\n", 456)

    fmt.Printf("%f\n", 78.9)

    fmt.Printf("%e\n", 123400000.0)
    fmt.Printf("%E\n", 123400000.0)

    fmt.Printf("%s\n", "\"string\"")

    fmt.Printf("%q\n", "\"string\"")

    fmt.Printf("%x\n", "hex this")

    fmt.Printf("%p\n", &p)

    fmt.Printf("|%6d|%6d|\n", 12, 345)
}

fmt.Printf("|%6.2f|%6.2f|\n", 1.2, 3.45)
fmt.Printf("|%-6.2f|%-6.2f|\n", 1.2, 3.45)
fmt.Printf("|%6s|%6s|\n", "foo", "b")
fmt.Printf("|%-6s|%-6s|\n", "foo", "b")
s := fmt.Sprintf("a %s", "string")
fmt.Println(s)
fmt.Fprintf(os.Stderr, "an %s\n", "error")

Output result:

{1 2}
{x:1 y:2}
main.point{x:1, y:2}
main.point
true
123
1110
!
1c8
78.900000
1.234000e+08
1.234000E+08
"string"
"\"string\""
6865782074686973
0xc0000b4010
|    12|   345|
|  1.20|  3.45|
|1.20  |3.45  |
|   foo|     b|
|foo   |b     |
a string
an error

Go Basic Syntax ```

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