*Adds all of the values of the datapoints that pass through it*

The `sum`

transform sums up numeric values. Given the data:

```
[2,5,1,6]
```

running the transform `sum`

will give:

```
[2,7,8,14]
```

Since the transform returns all intermediate values, and usually we only want the total sum,
`if last`

is frequently used to filter all datapoints but the final one:

```
sum | if last
```

When run on the above data, this transform returns `[14]`

, which is the total sum of all datapoints in the stream.

One-To-One | Stateless | Peek | Input Schema | Output Schema |
---|---|---|---|---|

True | False | False |