sum

Computes the sum of values.

null values are ignored.

All primitive numeric types are supported: Byte, Short, Int, Long, Float, and Double.

sum also supports the "mixed" Number type, as long as the column consists only of the aforementioned primitive numbers. The numbers are automatically converted to a common type for the operation.

All operations on Double/Float/Number have the skipNaN option, which is set to false by default. This means that if a NaN is present in the input, it will be propagated to the result. When it's set to true, NaN values are ignored.

<!---FUN statisticModes -->

```kotlin
df.sum() // sum of values per every numeric column
df.sum { age and weight } // sum of all values in `age` and `weight`
df.sumFor(skipNaN = true) { age and weight } // sum of values per `age` and `weight` separately
df.sumOf { (weight ?: 0) / age } // sum of expression evaluated for every row

df.age.sum()
df.groupBy { city }.sum()
df.pivot { city }.sum()
df.pivot { city }.groupBy { name.lastName }.sum()

See statistics for details on complex data aggregations.

See column selectors for how to select the columns for this operation.