A reminder about selections
A selection in iolite is simply a named (and grouped) period of time. Data processing in iolite revolves around groups of these selections and groups of different types. A selection’s period of time is defined by a start time and an end time. Of course things can be more complicated when you throw in linked selections and other properties, but for now let’s consider a few ways we can manipulate selections with python.
A reminder about python
Python is a programming language that you can write add ons and other scripts in for iolite 4. To read more about python and the various ways you can use it in iolite, see here.
Examples
Adjusting all the selections in a group
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# first we get the desired selection group by name and assign it to a variable called 'sg':
sg = data.selectionGroup('GroupName')
# then we use a for loop to iterate over all the selections in the group:
for s in sg.selections():
s.startTime = s.startTime.addSecs(2)
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Creating selections based on some arithmetic
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from iolite.QtCore import QDateTime
# Establish a start time using a specific format
start = QDateTime.fromString('2020-02-06 12:00:00.000', 'yyyy-MM-dd hh:mm:ss.zzz')
# Create a group named "TestGroup" of type "Sample"
group = data.createSelectionGroup('TestGroup', data.Sample)
duration = 20 # Selection duration in seconds
gap = 2 # Gap between selections in seconds
N = 30 # Number of selections to create
# Create the selections according to the parameters above:
for i in range(0, N):
this_start = start.addSecs(i*(duration + gap))
this_end = this_start.addSecs(duration)
data.createSelection(group, this_start, this_end, 'Sel%i'%(i))
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Split selection into several sub selections
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s = data.activeSelection() # Get the active selection
dest_group = data.createSelectionGroup('Split', data.Sample) # Create a group called split
N = 20 # Set the number of selections to split into
# Calculate the duration of each sub-selection
dur = (s.endTime.toMSecsSinceEpoch() - s.startTime.toMSecsSinceEpoch())/(1000.0*N)
ps = None # Used to keep track of previous selection
# Work out the start and end time for each sub-selection and add it to the group
for i in range(0, N):
if not ps:
this_start = s.startTime
else:
this_start = ps.endTime
this_end = this_start.addMSecs(1000.0*dur)
ps = data.createSelection(dest_group, this_start, this_end, 'Split%i'%(i))
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