Golang make vs new
In Golang, both make() and new() are used to allocate memory for certain data types. However, they serve different purposes and are used in different situations.
make()
The make function is used to create slices, maps, and channels. It initializes the data structure to its zero value and then allocates memory for the specified data type.
The syntax for make is:
...
make(type, size)
...
The type parameter indicates the data type of the structure and size determines the number of elements to allocate. An additional capacity parameter can also be specified, which specifies the memory to be allocated for the data type. When a capacity is specified, it can be termed a buffered type.
package main
import "fmt"
func main() {
// make a slice of 5 integers
slice := make([]int, 5)
fmt.Println(slice)
// make a map of 5 integers
m := make(map[int]int, 5)
fmt.Println(m)
// make a channel of 5 integers
c := make(chan int, 5)
for i := 0; i < 5; i++ {
c <- i
}
close(c)
for v := range c {
fmt.Println(v)
}
}
new()
The new function is used to create pointer values for any data type. It allocates zero-valued memory for the specified data type and returns a pointer to that memory.
The syntax for new is:
...
new(type)
...
This is useful when you want to create a pointer to a data type, but don’t want to initialize it with a value.
package main
import "fmt"
func main() {
// create a pointer to an integer
i := new(int)
fmt.Println(i)
// create a pointer to a string
s := new(string)
fmt.Println(s)
// create a pointer to a slice
sl := new([]int)
fmt.Println(sl)
// create a pointer to a map
m := new(map[int]int)
fmt.Println(m)
// create a pointer to a channel
c := new(chan int)
fmt.Println(c)
}
Make vs New
One key difference between make and new functions is memory allocation. make allocates memory for the data structure, while new allocates zero-valued memory for the data type.
Another difference is handling zero values. The make function initializes the data structure to its zero value, which is useful for slices, maps, and channels, as they have specific zero values. On the other hand, the new function, only allocates zero-valued memory, without initializing it.
Another difference comes in terms of limitations and usage. The make function can only be used to create slices, maps, and channels. The new function can be used to create pointers to any data type. Though make is limited in use cases, it is optimized for specific data types, while new is more generic.
Conclusion
In this article, we covered the make and new functions in Golang. We saw how they are used to allocate memory for different data types, and the differences between them. Hope you found this helpful article
