When you give a query command for a numeric value, Praat sometimes writes the numeric value --undefined-- into the Info window (two hyphens at both sides of the word). This happens if the value you ask for is not defined, as in the following examples:
In a Praat script, this value is simply represented as "undefined". You use it to test whether a query command returned a valid number:
select Pitch hallo
meanPitch = Get mean... 0.1 0.2 Hertz Parabolic
if meanPitch = undefined
# Take some exceptional action.
# Take the normal action.
In text files, this value is written as --undefined--. In binary files, it is written as a big-endian IEEE positive infinity. In memory, it is the ANSI-C constant HUGE_VAL, which equals infinity on IEEE machines.
© ppgb, April 14, 2004