apply , , NA (""), "NA" ( , NA "" - c(x[!is.na(x)], x[is.na(x)]))
mydf[] <- t(apply(mydf, 1, function(x) c(x[!is.na(x)], rep("", sum(is.na(x))))))
mydf
# Pro1 Pro2 Pro3 Pro4
#Pathway1 Woot Yeet Yike
#Pathway2 Dang Yike
#Pathway3 Blah Try Lost
order
mydf[] <- t(apply(mydf, 1, function(x) x[order(is.na(x))]))