Go Slices Are Dynamic Arrays

Jan 11, 2021

Despite what’s said about Go slices in this blog post, if you really know what dynamic arrays are internally, you should immediately recognize the resemblance between Go’s slices and a dynamic array.

To be more precise, a typical dynamic array implementation is like

typedef struct {
int *array;
int used;
int size;
} Array;

Where the underlying array is allocated by malloc and will be reallocted by realloc if need be. Now, let’s take a look at the internals of a Go slice. Oh, it has three parts too. A pointer to an underlying array, a length, and a capacity. Sounds familiar, right? How should we call such a structure if not “dynamic arrays” then?