merge - Have nomatch return value as-is using match function in R -
merge - Have nomatch return value as-is using match function in R -      i have much larger existing dataframe. smaller  illustration replace of variables (replace state (df1)) newstate (df2) according column "first." issue values returned na since of names matched in new dataframe (df2).   existing dataframe:    state = c("ca","wa","or","az") first = c("jim","mick","paul","ron") df1 <- data.frame(first, state)        first state     1   jim    ca     2  mick    wa     3  paul    or     4   ron    az    new dataframe match existing dataframe       state = c("ca","wa") newstate = c("tx", "la") first =c("jim","mick") df2 <- data.frame(first, state, newstate)    first state newstate 1   jim    ca       tx 2  mick    wa       la    tried  utilize match returns na "state" matching "first" variable df2 not found in ori...