Declare or Make a Slice in Go: Which Approach is Best?

Declare or Make a Slice? Understanding the Difference in Go

When working with slices in Go, developers often encounter two primary methods for creating them: declaring an empty slice using var s []int and using the make function as in s := make([]int, 0). This article delves into the nuances between these approaches to provide a clear understanding of their differences.

Declare Slice: var s []int

The var s []int declaration creates an uninitialized slice that does not allocate any memory. The underlying pointer of the slice, s, is set to nil, indicating that it does not point to any valid memory location. This declaration is typically used when the exact size of the slice is not known in advance.

Make Slice: s := make([]int, 0)

In contrast, s := make([]int, 0) both declares and initializes a slice. It allocates memory for a slice with zero elements and assigns the pointer to the slice variable s. This approach is suitable when the exact size of the slice is known upfront.

Which Approach is Better?

The appropriate choice between these two methods depends on the specific use case. Generally, it is considered idiomatic to use var s []int when the number of elements is not known in advance. This approach avoids wasting memory and allows for dynamic slice growth.

On the other hand, s := make([]int, 0) is advantageous when the slice size is known at the time of declaration. It ensures that memory is allocated only for the specified number of elements, preventing unnecessary wastage.

The above is the detailed content of Declare or Make a Slice in Go: Which Approach is Best?. For more information, please follow other related articles on the PHP Chinese website!