# Count

`count.Rd`

Count the number of rows for each group when we have `GroupedData`

input.
The resulting SparkDataFrame will also contain the grouping columns.

This can be used as a column aggregate function with `Column`

as input,
and returns the number of items in a group.

## Usage

```
count(x)
n(x)
# S4 method for GroupedData
count(x)
# S4 method for Column
count(x)
# S4 method for Column
n(x)
```

## Examples

```
if (FALSE) {
count(groupBy(df, "name"))
}
if (FALSE) count(df$c)
if (FALSE) n(df$c)
```