getSheetID<-function(URL){
regmatches(URL, regexpr("/spreadsheets/d/\\K[^/]+", URL, perl=TRUE))[1]
}
x <- "https://docs.google.com/spreadsheets/d/crazyLongIDstring/edit"
getSheetID(x)
Z2V0U2hlZXRJRDwtZnVuY3Rpb24oVVJMKXsKICByZWdtYXRjaGVzKFVSTCwgcmVnZXhwcigiL3NwcmVhZHNoZWV0cy9kL1xcS1teL10rIiwgVVJMLCBwZXJsPVRSVUUpKVsxXQp9Cgp4IDwtICJodHRwczovL2RvY3MuZ29vZ2xlLmNvbS9zcHJlYWRzaGVldHMvZC9jcmF6eUxvbmdJRHN0cmluZy9lZGl0IgpnZXRTaGVldElEKHgpCgo=