icecube.dataio – python bindings to Data I/O utilities

class icecube.dataio.I3File

Simple sequential reader/writer of .i3 files.

Writing

Reading

Used to indicate the mode with which to open a file. Possible values are Reading and Writing. Obviously you can only push frames onto a Writing file and pop frames from a Reading file.

I3File()

Create an I3File object w/o an actual associated file:

# not very useful
f = I3File()

open_file(path, mode = I3File.Reading)

Open file at path. Default mode is for reading:

# open for reading
i3file = I3File()
i3file.open_file("mydata.i3")

# open for writing
i3file2 = I3File()
i3file2.open_file("mydata.i3", I3File.Writing)

path may end in .i3 or .i3.gz for uncompressed or

gzip-compresed files (applies for both Reading and Writing)

I3File(path, mode = I3File.Reading)

Create an I3File, then call:

self.open_file(path, mode)

pop_frame()

Return the next frame of any type from the file:

frame = i3file.pop_frame()
print frame

pop_frame(stream)

Return the next frame of with stream type stream from the file:

frame = i3file.pop_frame(icetray.I3Frame.Geometry)
print frame

pop_physics()

Shorthand for:

pop_frame(icetray.I3Frame.Physics)

push(frame)

Push frame onto file (file must be open for writing):

frame = icetray.I3Frame(icetray.I3Frame.Physics)
i3file = I3File("generated.i3.gz", I3File.Writing)
i3file.push(frame)

close()

Close the file.

rewind()

Close and reopen the file to the beginning.

more()

Returns true if there are more frames available. This prints all the event ids in a file:

i3f = I3File("mydata.i3")
while i3f.more():
  phys = i3f.pop_frame()
  print phys['I3EventHeader'].EventID

You can also use the iterator interface rather than writing an explicit loop.

next()

Returns the next frame, if available, else throws StopIteration. This is part of the python ‘iterator protocol’; this function combined with __iter__(), gets you iteration in loops and list comprehensions (see __iter__() below):

__iter__()

Return an iterator to the I3File (just a freshly-opened copy of the I3File object itself, since I3File implements the iterator protocol). The I3File class supports standard python iteration. This means you can use the I3File in looping contexts:

i3f = I3File("mydata.i3")
for frame in i3f:
    print frame

or minus the intermediate variable i3f:

for frame in I3File('mydata.i3'):
    print frame

and list comprehensions. For instance this gets the EventID of all physics frames in the file mydata.i3:

eventids = [frame['I3EventHeader'].EventId
            for frame in I3File('mydata.i3')
            if frame.GetStop() == icetray.I3Frame.Physics]