Expression evaluation

Feature references

An expression may reference any feature inspection so far in the workflow for the current part.

To reference the entered value of a numeric feature (or the numeric field of a categorical feature), use $x, where x is the balloon label of the feature.
To reference the selected value of a categorical feature (even if it has a numeric value as well), use $$x, where x is the balloon label of the feature.
Features without balloon labels cannot be referenced.

The following logical operations are supported:
Operator	Evaluates to `true` only when...	Example
`==`	Both arguments are equal	`1 == 2` → `false`
`!=`	Both arguments are not equal	`1 != 2` → `true`
`<`	Left argument is smaller	`1 < 2` → `true`
`>`	Right argument is smaller	`1 > 2` → `false`
`<=`	Left argument is smaller or equal	`1 <= 2` → `true`
`>=`	Right argument is smaller or equal	`1 >= 2` → `false`
`or`	Either input is true	`(1 > 2) or (4 > 3)` → `true`
`and`	Both inputs are true	`(1 > 2) and (2 >= 3)` → `false`
`xor`	Exactly one input is true	`true xor true` → `false`
`not`	The input is false	`not true` → `false`

Logical operations can be infinitely nested. For example, ((1 == 1) and (1 < 2)) or not ((3 > 4) and (2 > 1)) evaluates to true.

The following functions are supported:
Name	Description	Example
`abs(x)`	Returns the absolute value of x	`abs(-3)` → `3`
`round(x)`	Round x to the nearest integer	`round(1.5)` → `2`
`ceil(x)`	Rounds x up	`ceil(1.1)` → `2`
`floor(x)`	Rounds x down	`ceil(2.9)` → `2`
`log(x)`	Computes the logarithm base e of x	`log(5)` → `1.60944...`
`log(x, b)`	Computes the logarithm base b of x	`log(5, 10)` → `0.69897...`
`sqrt(x)`	Returns the square root of x	`sqrt(64)` → `8`
`min(...)`	Returns the smallest of its arguments	`min(1, 2, 3)` → `1`
`max(...)`	Returns the largest of its arguments	`max(1, 2, 3)` → `3`
`mean(...)`	Returns the average of its arguments	`mean(1, 5, 10)` → `2.666...`
`median(...)`	Returns the middle of its arguments. If there are an even number of arguments, it returns the average of the middle two.	`median(2, 5, 7)` → `5`
`std(...)`	Returns the standard deviation of its arguments.	`mode(1, 5, 13, 20)` → `8`
`sum(...)`	Returns the sum of its arguments.	`sum(1, 2, 3, 4)` → `10`

The following trigonometry functions are also available and operate in radians:

Where a indicates an inverse function and h indicates a hyperbolic function.