How to Print in GoLang

It has always been a challenge for me when working with GoLang and trying to print out something, usually during debugging and or various other tasks while building.

Let's have a quick look at what we should use and when should we use it with regards to printing in GoLang.

PS: Try to read through, we will make it fast as much as possible.

Personally I usually use about 7 of the print methods in-built in GoLang, which include: fmt.Print, fmt.Println, fmt.Printf, fmt.Sprint, fmt.Sprintln, fmt.Sprintf and fmt.Fprint. In Go (golang), the fmt package provides several printing functions for different use cases.

---

1. fmt.Print

• Purpose: Prints values directly to the console.
• No Formatting Specifiers: Just concatenates values as strings.
• No Line Break: No newline at the end, so subsequent output appears on the same line.

Example:

fmt.Print("Hello", " ", "World!")

Output:

Hello World!

---

2. fmt.Println

• Purpose: Prints values directly to the console, with a newline at the end.
• No Formatting Specifiers: Concatenates values with spaces between them.
• Auto Line Break: Automatically adds a newline at the end.

Example:

fmt.Println("Hello", "World!")

Output:

Hello World!

---

3. fmt.Printf

• Purpose: Prints values directly to the console with formatting specifiers.
• Formatting Specifiers: Uses %s, %d, %v, etc.
• No Auto Line Break: Doesn't automatically add a newline; you need to specify \n.

Example:

fmt.Printf("Name: %s, Age: %d\n", "Alice", 25)

Output:

Name: Alice, Age: 25

---

4. fmt.Sprint

• Purpose: Concatenates values into a string without formatting.
• No Printing: Doesn't print to the console, just returns the string.
• No Line Break: No newline included.

Example:

message := fmt.Sprint("Hello", " ", "World!")
fmt.Println(message)

Output:

Hello World!

---

5. fmt.Sprintln

• Purpose: Concatenates values into a string with a newline.
• No Printing: Doesn't print to the console, just returns the string.
• Auto Line Break: Adds a newline to the returned string.

Example:

message := fmt.Sprintln("Hello", "World!")
fmt.Print(message)

Output:

Hello World!

---

6. fmt.Sprintf

• Purpose: Formats values into a string using format specifiers.
• No Printing: Doesn't print to the console, just returns the formatted string.
• No Line Break: No newline unless explicitly added.

Example:

message := fmt.Sprintf("Name: %s, Age: %d", "Alice", 25)
fmt.Println(message)

Output:

Name: Alice, Age: 25

---

7. fmt.Fprint

• Purpose: Writes formatted output to a specified writer (like files, buffers, etc.).
• For Advanced Usage: Typically used with files or custom outputs.

Example:

import (
    "os"
    "fmt"
)

func main() {
    fmt.Fprint(os.Stdout, "Hello World!")
}

Output:

Hello World!

---

Summary Table:

Function	Purpose	Returns a String?	Directly Prints?	Supports Formatting?	Auto Newline?
fmt.Print	Simple printing, no newline	❌	✅	❌	❌
fmt.Println	Simple printing with newline	❌	✅	❌	✅
fmt.Printf	Formatted printing	❌	✅	✅	❌
fmt.Sprint	String concatenation (no print)	✅	❌	❌	❌
fmt.Sprintln	String concatenation with newline	✅	❌	❌	✅
fmt.Sprintf	Formatted string creation	✅	❌	✅	❌
fmt.Fprint	Formatted printing to a writer	❌	✅	✅	❌

Take a look at my YouTube and GitHub

• YouTube
• GitHub