Capacity

2 articles

Go 12 Sep 2026 4 min read

Limit Go Slice Capacity with slices.Clip

A Go slice can be short while still carrying much more capacity than its current length. That extra capacity is useful when more elements are expected, but sometimes code should hand off a slice without leaving room for an append to reuse the same tail. slices.Clip gives that intent a direct operation. Clip returns a slice with the same elements and length, but its capacity is reduced to its length.

Go Slices

Go 11 Sep 2026 5 min read

Reserve Go Slice Capacity with slices.Grow

Repeated append calls can force a Go slice to move to a larger backing array when its capacity runs out. If code already knows that several more elements are about to arrive, slices.Grow can reserve enough room before those appends happen. The key detail is that slices.Grow changes capacity when needed, not length. Existing elements stay in place logically, and the returned slice still contains the same number of elements.

Go Slices