google sheets - Counting number of occurrences in column?

Question

What would be a good approach to calculate the number of occurrences in a spreadsheet column? Can this be done with a single array formula?

Example (column A is input, columns B and C are to be auto-generated):

|   A   |   B   |   C   |
+-------+-------+-------+
| Name  | Name  | Count |
+-------+-------+-------+
| Joe   | Joe   |     2 |
| Lisa  | Lisa  |     3 |
| Jenny | Jenny |     2 |
| Lisa  |       |       |
| Lisa  |       |       |
| Joe   |       |       |
| Jenny |       |       |

Answer 1

A simpler approach to this

At the beginning of column B, type

=UNIQUE(A:A)

Then in column C, use

=COUNTIF(A:A, B1)

and copy them in all row column C.

Edit: If that doesn't work for you, try using semicolon instead of comma:

=COUNTIF(A:A; B1)