How Does Go Efficiently Compare Strings Under the Hood?

String Comparison in Go: Unveiling the Hidden Mechanisms

In Go, string comparison is performed seamlessly without requiring explicit function calls. However, behind the scenes, the Go runtime plays a crucial role in optimizing these comparisons.

As the Go specification states, Go supports string comparison using the equality (==) and inequality (!=) operators. But what happens when comparing two strings?

The Go runtime takes a pragmatic approach to string comparisons. By delegating comparisons to the runtime.eqstring function, it ensures efficient comparisons for both literal strings and runtime-generated strings.

For literal strings stored in the Go program's text section, the runtime performs a quick short-circuit check to determine if the operands are identical in memory. If so, the result is determined without further processing.

In cases where the strings are not identical in memory, runtime.eqstring takes over and performs a byte-by-byte comparison of the strings. This process incurs an O(n) time complexity, where n represents the length of the shorter string.

For non-literal strings created during runtime, the runtime.eqstring function handles the comparison using a custom implementation optimized for the dynamic nature of such strings.

It's important to note that unless you're directly involved in compiler or runtime development, the intricacies of string comparison should not be a concern to most Go developers. The operators defined in the Go spec simplify the process, allowing developers to rely on expected behavior and optimized comparisons.

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