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callcount

slices.Index

standard library

The 2448th most-called standard-library function by production calls. Called 350 times across 91 modules; 250 of those run outside tests and generated code.

2% in production calls vs 2026-W37 (245 → 250)

All of slices → Docs on pkg.go.dev ↗

prod calls
250
non-test, non-generated
all calls
350
total callsites
modules
91
distinct callers
in loop
28%
of prod calls
in tests
28%
99 calls
resolved
100%
to a known target

resolution mix

How each call resolves

How each call was attributed. Only resolved kinds, where the target function is known, count toward the ranking. Interface dispatch and unresolved receivers are reported separately and never guessed. Read the taxonomy →

  • Package function100%A direct call to an exported package function, resolved by type.

estimate

Experimental

Estimated relative cost

Roughly 0.00× the estimated relative cost of fmt.Sprintf . Benchmarked at 3.96 ns/op × 250 production calls, normalized so fmt.Sprintf = 1.0.

This is not dollars and not a verdict. Per-op time depends heavily on inputs (argument sizes, contention, patterns), the benchmark ran on a single machine (darwin/arm64 (Apple Silicon), go1.26.0), and static call counts are not runtime frequency. How this is estimated →

who calls this

Notable callers

Production calls into Index from notable Go projects. Open one on the map to see what else it hammers.

where it's called

Callsites in the wild

12 representative callsites of 350, prioritizing in-loop and non-test usage. We link to source, never display it.

Index · 12 of 350 callsites

top callers

The modules that reach for it

The modules that call Index most in this snapshot.

  • github.com/microsoft/typescript-go4613%
  • github.com/tailscale/tailscale237%
  • tailscale.com237%
  • github.com/cilium/cilium175%
  • github.com/weaviate/weaviate165%

siblings

More from slices

The other most-called functions in this package. See all →