Counting the number of elements with the values of x in a vector

Question

I have a vector of numbers:

numbers <- c(4,23,4,23,5,43,54,56,657,67,67,435,
         453,435,324,34,456,56,567,65,34,435)

How can I have R count the number of times a value x appears in the vector?

Answer 1

You may simply use the table() method:

> a <- table(numbers) > a \snumbers
4 5 23 34 43 54 56 65 67 324 435 453 456 567 657 324 435 453 456 567 657 324 435 453 456 567 657 324 435 4
2 1 2 1 2 1 2 1 2 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Then you can subset it:

> a[names(a)==435]
435
3
Or convert it into a data.frame if you're more comfortable working with that:

> as.data.frame(table(numbers)) numbers Freq 1 4 2 2 5 1 3 23 2 4 34 2