Is there a way to determine how many rows in a dataset have the same categorical variable for multiple conditions (columns)?

Question

For example, i have the dataset below where 1 = yes and 0 = no, and I need to figure out how many calls were made by landline that lasted under 10 minutes.

Image of example dataset

Answer 1

We can use sum

sum(df1[, "under 10 minutes"])

If two columns are needed

colSums(df1[, c("landline", "under 10 minutes")])

If we are checking both columns, use rowSums

sum(rowSums(df1[, c("landline", "under 10 minutes")], na.rm = TRUE) == 2)