What Are The Differences Between “=” And “<-" Assignment?

In Go, both the = and <- operators are used for assignment, but they serve different purposes and are used in different contexts. Here’s a breakdown of the key differences between them:

1. = (Regular Assignment Operator):

• Purpose: The = operator is used for regular assignment in Go. It assigns a value to a variable, and it’s used within functions, including when modifying the value of existing variables.
• Usage: It can be used for initializing variables and reassigning values to already declared variables.

Example:

package main

import "fmt"

func main() {
    var x int = 10    // Regular assignment with declaration
    x = 20            // Reassigning the value of x

    fmt.Println(x)     // Output: 20
}

In this example:

• The = operator assigns a value to x (both when initializing it and later when reassigning its value).

2. <- (Channel Assignment Operator):

• Purpose: The <- operator is used for sending or receiving values on Go channels. It is not used for regular variable assignment like =.
  • Sending values: You use <- to send a value into a channel.
  • Receiving values: You use <- to receive a value from a channel.

Example (Sending and Receiving):

package main

import "fmt"

func main() {
    ch := make(chan int)  // Create a channel of type int

    go func() {
        ch <- 42  // Send the value 42 into the channel
    }()

    value := <-ch  // Receive the value from the channel
    fmt.Println(value)  // Output: 42
}

In this example:

• ch <- 42 sends the value 42 into the channel ch.
• value := <-ch receives the value from the channel ch and assigns it to value.

Key Differences:

Additional Notes:

• =: Works with regular variables. You use it to assign values to already declared variables or to declare and assign values simultaneously in some cases.
• <-: Specifically for channels, and it’s used for communication between goroutines. You cannot use <- for regular variable assignment.

Example with both in a program:

package main

import "fmt"

func main() {
    var a int = 10  // Regular assignment using `=`

    ch := make(chan int)  // Channel assignment

    go func() {
        ch <- 42  // Sending value to the channel
    }()

    a = <-ch  // Receiving value from the channel and assigning it to `a`

    fmt.Println(a)  // Output: 42
}

In this case:

• a = 10 uses the = operator for regular variable assignment.
• ch <- 42 and a = <-ch use the <- operator for sending and receiving values to/from a channel.