I am using R. For this random data set that I generated, I created the following contingency table:

```
library(memisc)
library(dplyr)
set.seed(123)
v1 <- c("2010-2011","2011-2012", "2012-2013", "2013-2014", "2014-2015")
v2 <- c("A", "B", "C", "D", "E")
v3 <- c("Z", "Y", "X", "W" )
v4 <- c("data_1", "data_2", "data_3", "data_4" )
dates <- as.factor(sample(v1, 1000, replace=TRUE, prob=c(0.5, 0.2, 0.1, 0.1, 0.1)))
types <- as.factor(sample(v2,1000, replace=TRUE, prob=c(0.3, 0.2, 0.1, 0.1, 0.1)))
types2 <- as.factor(sample(v3, 1000, replace=TRUE, prob=c(0.3, 0.5, 0.1, 0.1)))
names <- as.factor(sample(v3, 1000, replace=TRUE, prob=c(0.3, 0.5, 0.1, 0.1)))
var = rnorm(1000,10,10)
problem_data = data.frame(var,dates, types, types2, names)
summary <- xtabs(~dates+names+types+types2, problem_data)
t = ftable(summary, row.vars=1, col.vars=2:4)
show_html(t)
```

If I wanted to add a row containing "Grand Totals" to the bottom of this table, I could do this as follows:

```
totals <- problem_data %>% group_by(names, types, types2) %>% summarise(totals = n())
memisc::show_html(rbind(t, totals = totals$totals), varinfront = FALSE)
```

**Is it possible to add "totals" at arbitrary positions in this contingency table?**

For example, suppose I want to find the totals for the first two rows (2010-2011, 2011-2012), and then insert this total in this table at the third row. I can calculate the totals for the firs two rows:

```
first_two_rows = subset(problem_data, dates %in% c("2010-2011","2011-2012"))
totals_first_two_rows <- first_two_rows %>% group_by(names, types, types2) %>% summarise(totals = n())
```

**But how can this "totals_first_two_rows" be added to the third position of the contingency table?** Using this stackoverflow post (Add new row to dataframe, at specific row-index, not appended?), I tried using the function provided in the answer:

```
insertRow <- function(existingDF, newrow, r) {
existingDF[seq(r+1,nrow(existingDF)+1),] <- existingDF[seq(r,nrow(existingDF)),]
existingDF[r,] <- newrow
existingDF
}
insertRow(t, totals_first_two_rows, 3)
```

But this returns the following error:

```
Error in `[<-`(`*tmp*`, seq(r + 1, nrow(existingDF) + 1), , value = existingDF[seq(r, :
subscript out of bounds
```

**Can someone please show me how to fix this problem?**

Thanks!