GetSlice

class baseband_tasks.shaping.GetSlice(ih, item)

Bases: ChangeSampleShapeBase

Slice a stream and index or slice its samples.

Useful to select part of a stream, possibly in combination with selecting, e.g., a specific frequency band or polariazation.

Parameters:

ihtask or baseband stream reader

Input data stream.

itemslice or tuple of slice, int, or array of int

Anything that can slice a numpy array. Should be a slice for the time axis.

See also

GetItem

index or slice the samples, without slicing the time axis

Reshape

to reshape the samples

Transpose

to transpose sample axes

ReshapeAndTranspose

to reshape the samples and transpose the axes

ChangeSampleShape

to change the samples with a user-supplied function.

Examples

The VDIF example file from Baseband has 8 threads. To ignore the first and last 10 samples, one could do:

>>> import numpy as np, astropy.units as u, baseband
>>> from baseband_tasks.shaping import GetSlice
>>> fh = baseband.open(baseband.data.SAMPLE_VDIF)
>>> gsh = GetSlice(fh, slice(10, -10))
>>> gsh.shape
(39980, 8)
>>> fh.close()

Methods Summary

task(data)

No-op task for default case of no sample slicing.

Methods Documentation

task(data)

No-op task for default case of no sample slicing.

Is overridden in initializer if sample slicing is needed.