build HTML anchors for pubmed ids
build_anchors(pmids)
character() vector (maybe numeric) of pubmed ids
anchors in a character vector
build_anchors(c("12345", "23456"))
#> 12345
#> "<a href=\"https://pubmed.ncbi.nlm.nih.gov/12345\">12345</a>"
#> 23456
#> "<a href=\"https://pubmed.ncbi.nlm.nih.gov/23456\">23456</a>"