Semantic Versioning 2.0.0

Given a version number MAJOR.MINOR.PATCH, increment the:

MAJOR version when you make incompatible API changes,
MINOR version when you add functionality in a backwards compatible manner, and
PATCH version when you make backwards compatible bug fixes.

Additional labels for pre-release and build metadata are available as extensions to the MAJOR.MINOR.PATCH format.

Is “v1.2.3” a semantic version?

No, “v1.2.3” is not a semantic version. However, prefixing a semantic version with a “v” is a common way (in English) to indicate it is a version number. Abbreviating “version” as “v” is often seen with version control. Example: git tag v1.2.3 -m "Release version 1.2.3", in which case “v1.2.3” is a tag name and the semantic version is “1.2.3”.

https://semver.org/#is-there-a-suggested-regular-expression-regex-to-check-a-semver-string

Is there a suggested regular expression (RegEx) to check a SemVer string?

There are two. One with named groups for those systems that support them (PCRE [Perl Compatible Regular Expressions, i.e. Perl, PHP and R], Python and Go).

See: https://regex101.com/r/Ly7O1x/3/

^(?P<major>0|[1-9]d*).(?P<minor>0|[1-9]d*).(?P<patch>0|[1-9]d*)(?:-(?P<prerelease>(?:0|[1-9]d*|d*[a-zA-Z-][0-9a-zA-Z-]*)(?:.(?:0|[1-9]d*|d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:+(?P<buildmetadata>[0-9a-zA-Z-]+(?:.[0-9a-zA-Z-]+)*))?$

And one with numbered capture groups instead (so cg1 = major, cg2 = minor, cg3 = patch, cg4 = prerelease and cg5 = buildmetadata) that is compatible with ECMA Script (JavaScript), PCRE (Perl Compatible Regular Expressions, i.e. Perl, PHP and R), Python and Go.

See: https://regex101.com/r/vkijKf/1/