user manual

111
Building CLEM Expressions
 Characters—Always use sing le backquotes like this ` . Fo r example, note the character d in
the function stripchar(`d`,"drugA"). The only exception to this is when you a r e using an integer
to refer to a sp
ecific character in a string. F or example, note the characte r 5 in the function
lowertoupper("druga"(5)) —> "A". Note: On a standard U.K. and U.S. keyboard, the key for the
backquote character ( gra ve accent, Unicode 0060) can b e found just below the Esc key.
 Fields—Fields are typicall y unquote d when used in CLEM expressions (subscr(2,arrayID))
—> CHAR). You
can u se single quotes when necess ary to enclose spaces or other special
characters ('Order Number'). Fields that are quoted but undefined in the data set will be
misread as strings.
 Parameters—Always use single quotes ('$P-threshold').
Expressions and Conditions
CLEM expressions c an return a result (used when deriving new values)—for examp le:
Weight * 2.2
Age + 1
sqrt(Signal-Echo)
Or, they c an evaluate true or false (used when selecting on a condition)—for example:
Drug = "drugA"
Age < 16
not(PowerFlux) and Power > 2000
You can combine o perators and f unctions arbitrarily in CLEM expres sions—for ex
ample:
sqrt(abs(Signal)) * max(T1, T2) + Baseline
Bracke ts and operator precedence determine the order in which the expressi on is evaluated. In this
example, the order of evalua tion 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, oper ations that are performed first to op erations
that are performed last) is as follows:
 Functi on arguments
 Functi on calls
 xx
 x / mod div rem
 + –
 > < >= <= /== == = /=