x <- "CVEGEO=0901500011337<BR>CVE_ENT=09<BR>CVE_MUN=015<BR>CVE_LOC=0001<BR>CVE_AGEB=1337<BR>"
regmatches(x, regexpr("_MUN=\\K\\d+", x, perl=TRUE))
regmatches(x, regexpr("_AGEB=\\K\\d+", x, perl=TRUE))