Go has become increasingly popular in recent years, especially in my local area. It has been consistently displacing other backend languages like Ruby, Python, C# and Java. Go is wanted for its simplicity, explicitness, speed, and low memory consumption. Many developers that are new to the language, or new to a language that can handle memory directly using pointers end up misusing those pointers. What Is a Pointer? A pointer is a variable that stores the address of a value, rather than the value itself. If you think of a computer's memory (RAM) as a JSON object, a pointer would be like the key, and a normal variable would be the value. { : } "pointer" "variableValue" Lets see one in action: main { name := setName(&name, )
	fmt.Println(name)
} { *ptr = newName
} package import "fmt" func main () // create a normal string variable "original" // pass in a pointer to the string variable using '&' "qvault" func setName (ptr * , newName ) string string // dereference the pointer so we can modify the value // and set the value to "qvault" This prints: qvault As you can see, because we have a pointer to the address of the variable we can modify its value, even within the scope of another function. If the value were not a pointer, this would not work: , main {
	name := setNameBroken(name, )
	fmt.Println(name)
} {
	ptr = newName
} package import "fmt" func main () "original" "qvault" func setNameBroken (ptr , newName ) string string prints: original Pointers can be useful, but in the same way that they are useful, they can be dangerous. For example, if we dereference a pointer that has no value, the program will panic. For this reason we always check if an error value is nil before trying to print it. Syntax 1. Creating a pointer: & newString := newStringPointer := &newString "" If you print that pointer you will see a memory address. main {
	newString := newStringPointer := &newString
	fmt.Println(newStringPointer)
} package import "fmt" func main () "" prints: 0xc00000e1e0 Which is the memory address of that variable in your machine. 2. Describing a pointer: * In a function signature or type definition, the * is used to designate that a value is a pointer. {
} func passPointer (pointer * ) string 3. Dereferencing a pointer: * It can be slightly confusing, but the * is used to describe a pointer and it is also used as an operator to dereference a pointer. {
	newStringVariable := *pointer } func derefPointer (pointer * ) string // newStringVariable is just a normal string When Should I Use a Pointer? There are probably many nuanced cases for when a pointer is a good idea, but I would guess that 95% of the time when you use a pointer, it should be for one the following reasons: 1. A function that mutates one of its parameters When I call a function that takes a pointer as an argument, I expect that my variable will be mutated. If you aren't mutating the variable in your function, then you probably shouldn't be using a pointer. 2. Better Performance If you have a string that contains an entire novel in memory it gets really expensive to copy that variable each time it is passed to a new function. It may be worthwhile to pass a pointer instead, which will save CPU and memory. This comes at the cost of readability however, so only make this optimization if you must. 3. Need a Nil Value Option Sometimes a function needs to know what something's value is, as well as if it exists or not. I usually use this when reading JSON to know if a field exists or not. For example, if a JSON object is: { : } ----> *name: "name" "qvault" "qvault" { : } ----------> *name: "name" "" "" ----------------------> * : {} name nil Thanks These are some rules of thumb for when to use pointers in your code. If you are unsure, and a normal value will work just fine, I would advise avoiding the pointer. Pointers are useful tools but can lead to nasty bugs or unreadable code quite easily. By Lane Wagner @wagslane Previously published at https://qvault.io/2019/09/25/the-proper-use-of-pointers-in-go-golang/

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