Created
February 14, 2016 23:34
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| strs = c("nomatch", "Odum 1969", "2001FACE_3b", "1800", "sdfghj1928qwer") | |
| strs_yrs = gsub(".*((19|20)[0-9]{2}).*", "\\1", strs) | |
| strs_yrs | |
| # [1] "nomatch" "1969" "2001" "1800" "1928" | |
| # Oops, strings with no year (or year from wrong century) are returned unchanged! Let's remove them separately: | |
| strs_haveyr = grepl("(19|20)[0-9]{2}", strs) | |
| strs_yrs[!strs_haveyr] = "" | |
| strs_yrs | |
| # [1] "" "1969" "2001" "" "1928" | |
| # (N.B. assumes only one year per string -- if several, will return only 1st one.) | |
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Thanks for this! I'm just trying it now.
*** This works great *** Just saved me going through a long list of differently formatted references to extract the year of publication.