r - how to assign a missing value in dataframe by another value of dataframe? -

my dataframe

col1 col2 col3 col4 abc        25    35 cde  asd   25    45 def        15    36 erf        23    69 erf  asd   25    36 erf  dfg   85    78 

convert

col1 col2 col3 col4  col5 abc        25    35    abc abc  asd   25    45    asd def        15    36    def erf        23    69    erf erf  asd   25    36    asd erf  dfg   85    78    dfg 

i need col5 value amnot getting it. have tried using ifelse code

data$col5 <- ifelse(data$col2 =="",levels(data$col1),levels(data$col2)) 

but getting wrong value.

as per @rolands comment

data$col5 <- ifelse(data$col2 =="",as.character(data$col1),,as.character(data$col2))