```
- platform: copy
source_id: sensor_filter
name: "Wasserstand"
filters:
- lambda: return x - 1000;
```

how do I get the result to plus

Multiplication by -1 doesn’t work

the sensor value is always below 1000 (for information)

```
- platform: copy
source_id: sensor_filter
name: "Wasserstand"
filters:
- lambda: return x - 1000;
```

how do I get the result to plus

Multiplication by -1 doesn’t work

the sensor value is always below 1000 (for information)

Why not `1000 - x`

or perhaps `-(x - 1000)`

Unfortunately you have to write return x at the beginning otherwise you get an error message

```
- platform: copy
source_id: sensor_filter
name: "Wasserstand"
filters:
- lambda: return - (x - 1000);
```

Now I understand it

I had assumed return x must always be together

Thanks for the hint

There’s also the absolute value c++ function abs().