I have the following keyvalue dataframe
keyval =  data.frame(key = c('facebook',  'facebook mai - android', 
         'facebook mai - ios', 'facebook remarketing','facebook ig', 
         'app - android', 'bing - sem broad', 'bing - trademark', 
         'google - sem broad' , 'google - trademark' , 'google display', 'pla', 
         'google retargeting') ,
          val = c(6,21,20,7,9,21,5,19,3,17,3,12,4))
and would like to use an ifelse statement to access the value when it corresponds but I'm not sure of how to write the second argument. 
the_value_i_want =  ifelse(data$Publisher %in% keyval$key , 
                            notsurehowtowrite this part ,'error'), 
 
     
     
     
    