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Channel Class

A Channel object describes a single channel from a CHOP. The CHOP Class provides many ways of accessing its individual channels. See Working with CHOPs in Python for more examples of how to use this class.


Members

validbool (Read Only):

True if the referenced chanel value currently exists, False if it has been deleted.

indexint (Read Only):

The numeric index of the channel.

namestr (Read Only):

The name of the channel.

ownerOP (Read Only):

The OP to which this object belongs.

exportslist (Read Only):

The (possibly empty) list of parameters this channel currently exports to.

valslist :

Get or set the full list of Channel values. Modifying Channel values can only be done in Python within a Script CHOP.

Methods

[index]float:

Sample values may be easily accessed from a Channel using the [] subscript operator.

  • index - Must be an numeric sample index. Wildcards are not supported.

To get the third sample from the channel, assuming the channel has 3 or more samples:

n = op('pattern1')
c = n['chan2'][2]

eval(index)float:

Evaluate the channel at the specified index sample index. If no index is given, the current index based on the current time is used.

  • index - (Optional) The sample index to evaluate at.

evalFrame(frame)float:

Evaluate the channel at the specified frame. If no frame is given, the current frame is used.

  • frame - (Optional) The frame to evaluate at.

evalSeconds(secs)float:

Evaluate the channel at the specified seconds. If no time is given, the current time is used.

  • secs - (Optional) The time in seconds to evaluate at.

numpyArray()numpy.array:

Returns this channels data as a NumPy array with a length equal to the track length.

destroy()None:

Destroy and remove the actual Channel this object refers to. This operation is only valid when the channel belongs to a scriptCHOP. Note: after this call, other existing Channel objects in this CHOP may no longer be valid.

average()float:

Returns the average value of all the channel samples.

min()float:

Returns the minimum value of all the channel samples.

max()float:

Returns the maximum value of all the channel samples.

Casting to a Value

The Channel Class implements all necessary methods to be treated as a number, which in this case evaluates its current value. Therefore, an explicit call to eval() is unnecessary when used in a parameter, or in a numeric expression.

For example, the following are equivalent in a parameter:

(float)n['chan1']
n['chan1'].eval()

The following are also equivalent, because the + 1 will implicitly cast the channel to a number:

n['chan1'].eval() + 1
n['chan1'] + 1

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