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Py4pd Library

The primary goal of py4pd was to bring the powerful tools of OpenMusic into the robust environment of PureData. This integration is considered highly significant. Similar efforts have been made in Max, with various approaches, such as the Bach Library and MozLib. In this section, we will introduce the basic functions inspired by OpenMusic and how they are emulated within PureData.

To use the objects we will present next you need to create a new patch with the object py4pd -lib py4pd.

PureData and Python

One major difference you’ll notice when using Python objects with py4pd is that they typically don’t operate with standard PureData types (such as numbers, symbols, or lists). Instead, they utilize a workaround inspired by the Bach Library, using pointers. Pointers are memory addresses, and in the context of PureData and py4pd, they appear as references like PyObject list <0x60610796f9d0> or PyObject int <0x6061079771d0>. So in almost all py4pd object the output will be something like these PyObject thing.

At first, this may seem weird, but it's actually very powerful. Using pointers allows us to work with different data types that PureData doesn't natively support.

For example, when performing partial tracking, we often need a data type like an array of arrays. Since PureData doesn't support this, being able to do Partial Tracking manipulation on PureData is hard and becomes quite difficult.

Another scenario is when you want to build complex sound structures with many variables, parameters (like specific reverb, filter, and others configurations attached to them). PureData’s native data types can’t represent these kinds of complex objects. However, using PyObject, this becomes possible.

A good demonstration of this can be seen in the py4pd-upic library, where sound events are represented as pointers like PyObject SvgEvent 0x60610796f9d0>.

To convert Python types to PureData types you need to use the py2pd object (and pd2py for PureData to Python) but you will see that this is just necessary when you want to use the data inside some standard Pd Object.

Next we will present the set of object that comes with py4pd. The library is also called py4pd, being the default library of the py4pd object. To load the library you need to use py4pd -lib py4pd.

List of Python Objects

Here, we present the core functions from OpenMusic along with some additional features. Some objects are still missing, this is because I implement them as I use them. If you notice any missing objects, please let us know (click here to reportq) -- most can be quickly implemented!

Logic Objects

Here some objects to be used when doing some logic.

  • py.isnone

    Check if the input is None.

  • py.and

    Check if all the inputs are True.

  • py.or

    Check if any of the inputs are True.

  • py.equal

    Check if two inputs are equal.

  • py>

    Check if the left input is greater than the right input.

  • py<

    Check if the left input is less than the right input.

  • py.if

    Evaluate a condition and return a result based on it.

  • py.gate

    Control the flow of execution based on conditions.

  • py.isin

    Check if a value exists within a collection.

Utils

Utilities to use py4pd.

  • py.print

    Print the specified message to the console.

  • py.raise

    Raise an exception (error) with the specified message.

  • py.type

    Return the type of the specified object.

Convert Pd to Python | Python to Pd

Convertions between Pd and Python.

  • py2pd

    Convert Python objects to a format compatible with Pure Data (if possible).

  • pd2py

    Convert Pure Data objects to a format compatible with Python.

List Functions

Functions to work with lists.

  • py.mklist

    Create a new list from the specified elements (require to specify the number of inputs).

  • py.len

    Return the length of the specified list or collection.

  • py.nth

    Retrieve the element at the specified index from a list.

  • py.append

    Add an element to the end of the specified list (like x-append on OpenMusic).

  • py.list

    Convert a given item into a list (like list on OpenMusic).

  • py.split

  • py.max

    Return the maximum value from a list or collection.

  • py.min

    Return the minimum value from a list or collection.

  • py.reduce

  • py.mattrans

    Perform matrix transposition on a specified matrix (like mattrans from OpenMusic).

  • py.rotate

    Rotate elements of a list by a specified number of positions.

  • py.flat

    Flatten a nested list into a single list (like flat on OpenMusic).

  • py.np2list

    Convert a numpy array to a list.

  • py.list2np

    Convert a list to a numpy array.

Loops

Function to create a Python loop inside PureData.

  • py.range

    Generate a sequence of numbers within a specified range.

  • py.iterate

    Iterate over elements in a collection.

  • py.collect

    Collect results from a sequence of operations into a list.

  • py.recursive

    Perform a recursive operation. It is best to check the example on py4pd package.

  • py.trigger

Math

Math functions.

  • py+

    Add two numbers or concatenate two strings.

  • py-

    Subtract one number from another.

  • py/

    Divide one number by another.

  • py.abs

    Return the absolute value of a number.

  • py//

    Perform floor division between two numbers.

  • py.round

    Round a number to the nearest integer or specified decimal places.

  • py.expr

    Evaluate a mathematical expression (Python list comprehension)

OpenMusic Objects

Objects to imitate some of the great OpenMusic objects.

  • py.rhythm-tree

  • py.arithm-ser

Image

Show images inside PureData.

  • py.show

    Show image (like picture from OpenMusic).

Music Convertions

Convertions useful for music.

  • py.f2mc

    Convert frequency to midicents.

  • py.mc2f

    Convert midicents to frequency.

  • py.mc2n

    Convert midicents to note name.

If you miss some OpenMusic object, please report to us!