how can I create a new data frame using exact rows from the old data frame in R Studio?

Question

I need to select the exact rows from the old data frame and create a new one. I need to choose rows which contain paired numbers (as 11, 22, 33, 44, 55, 66, 77, 88 and 99). How can I do this?

I tried using filter:

paired1 <- filter(paired1$Var1=='22')
# Error in UseMethod("filter") : 
#  no applicable method for 'filter' applied to an object of class "logical"

And with:

> with (paired1, sum (Freq[Var1 == '11' & '22']))
# Error in Var1 == "11" & "22" : 
#  operations are possible only for numeric, logical or complex types

Answer 1

For two digit numbers:

paired1[paired1$var1 %in% seq(11, 99, 11),]

Answer 2

We may use

subset(paired1, !nchar(sub("(\\d)\\1+", "", var1)))

-output

  var1
4   99
5   11
7   44
8  777
9  555

data

 paired1 <- data.frame(var1 = c(12, 13, 25, 99, 11, 42, 44, 777, 555, 3))