This help topic is for R version 2.9.0. For the current version of R, try https://stat.ethz.ch/R-manual/R-patched/library/utils/html/compareVersion.html
compareVersion {utils}R Documentation

Compare Two Package Version Numbers

Description

Compare two package version numbers to see which is later.

Usage

compareVersion(a, b)

Arguments

a, b

Character strings representing package version numbers.

Details

R package version numbers are of the form x.y-z for integers x, y and z, with components after x optionally missing (in which case the version number is older than those with the components present).

Value

0 if the numbers are equal, -1 if b is later and 1 if a is later (analogous to the C function strcmp).

See Also

package_version, library, packageStatus.

Examples

compareVersion("1.0", "1.0-1")
compareVersion("7.2-0","7.1-12")

[Package utils version 2.9.0 ]