Answered with help of user @thelatemail.
df = read.table(sep="",
header=T,
text="Name Age Rate
Aira 23 90
Ben 32 98
Cat 27 95")
df$Rate2 = df$Rate #create column 'Rate2' and make it equal to 'Rate' (duplicate).
Another option to duplicate, triplicate or 'n plicate':
#use ?replicate function, which replicates elements over vectors and lists.
n = 3 #replicate 3 new columns
df3 = cbind(df, replicate(n,df$Rate)) #replicate from column "Rate" in the df object
df3 #plot df3 output
Name Age Rate 1 2 3
1 Aira 23 90 90 90 90
2 Ben 32 98 98 98 98
3 Cat 27 95 95 95 95
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