Expressions and conditions

CLEM expressions can return a result (used when deriving new values).

For example:

Weight * 2.2
Age + 1
sqrt(Signal-Echo)

Or, they can evaluate true or false (used when selecting on a condition). For example:

Drug = "drugA"
Age < 16
not(PowerFlux) and Power > 2000

You can combine operators and functions arbitrarily in CLEM expressions. For example:

sqrt(abs(Signal)) * max(T1, T2) + Baseline

Brackets and operator precedence determine the order in which the expression is evaluated. In this example, the order of evaluation is:

• abs(Signal) is evaluated, and sqrt is applied to its result
• max(T1, T2) is evaluated
• The two results are multiplied: x has higher precedence than +
• Finally, Baseline is added to the result

The descending order of precedence (that is, operations that are performed first to operations that are performed last) is as follows:

• Function arguments
• Function calls
• xx
• x / mod div rem
• + –
• > < >= <= /== == = /=

If you want to override precedence, or if you're in any doubt of the order of evaluation, you can use parentheses to make it explicit. For example:

sqrt(abs(Signal)) * (max(T1, T2) + Baseline)