Slices

Go 10 Sep 2026 5 min read

Remove Consecutive Duplicates in Go with slices.Compact

If a Go slice contains repeated values next to each other, you don’t need to write an index-heavy loop to collapse them. Since Go 1.21, slices.Compact handles that operation directly for comparable element types. The word consecutive matters. Given []string{"api", "api", "web", "api"}, the result is []string{"api", "web", "api"}. The last "api" stays because it belongs to a different run. slices.Compact isn’t a general-purpose “unique values” function. What slices.Compact actually does slices.Compact replaces each consecutive run of equal elements with its first element. It modifies the slice’s backing array and returns a slice with the resulting length.

Go Slices

Go 10 Sep 2026 6 min read

Process Go Slices in Batches with slices.Chunk

Batching a slice sounds simple until the loop starts collecting edge cases: the final batch may be short, an empty input needs sensible behavior, and careless subslicing can leave each batch with capacity to overwrite later elements. Go 1.23 added slices.Chunk, which handles that bookkeeping and exposes the batches as an iterator. If you already have the data in a slice and want to process consecutive groups without first building a [][]T, it’s a useful small tool.

Go Slices