proio 0.12.467
Library for reading and writing proio files and streams
License: BSD-3-Clause

# proio for Python
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Proio is an event-oriented streaming data format based on Google's [protocol
buffers](https://developers.google.com/protocol-buffers/) (protobuf).  Proio
aims to add event structure and additional compression to protobuf in a way
that supports event data model serialization in medium- and high-energy
physics.  Additionally, proio
* supports self-descriptive data,
* is stream compatible,
* is language agnostic,
* and brings along many advantages of protobuf, including forward/backward
  compatibility.

For detailed information on the proio format and introductory information on
the software implementations, please see [DOI
10.1016/j.cpc.2019.03.018](https://doi.org/10.1016/j.cpc.2019.03.018).  This
work was inspired and influenced by [LCIO](https://github.com/iLCSoft/LCIO),
ProMC (Sergei Chekanov), and EicMC (Alexander Kiselev)

Also see the [main proio repository](https://github.com/proio-org/proio) for
additional information information.

## API
The API documentation is generated using Sphinx, and can be found
[here](https://proio-org.github.io/py-proio-docs/).

## Installation
Py-proio is maintained on [pypi](https://pypi.python.org/pypi/proio).  The
proio package can be installed via
`pip`:
```shell
pip install --user --upgrade proio
```

If you run into trouble importing proio, force upgrade the two dependencies
which are `protobuf` and `lz4`.

For information on what versions of Python are supported, please see the
[Travis CI page](https://travis-ci.org/proio-org/py-proio).

### Building the package
If you need to build the package (instead of just installing from pypi as
described above), you can do so with the fairly standard [setup.py](setup.py).
In this case, you need to have the Protobuf compiler (`protoc`) installed.
With `pip`:
```shell
python setup.py clean build_py
pip install --user --upgrade .
```
, or if you want to just build a source package:
```shell
python setup.py clean build_py sdist
```
, or if you want to build a wheel package:
```shell
python setup.py clean bdist_wheel
```
.  Note that the `build_py` command is responsible for generating the Protobuf
code with `protoc`, and needs to be called explicitly in the pip and source
package case.

## Examples
### Manipulating data model objects (EIC Particle)
```python
import proio
import proio.model.eic as model

test_filename = 'test_file.proio'

with proio.Writer(test_filename) as writer:
    event = proio.Event()
    
    parent = model.Particle()
    parent.pdg = 443
    parent.p.x = 1
    parent.mass = 3.097
    parent_id = event.add_entry('Particle', parent)

    child1 = model.Particle()
    child1.pdg = 11
    child1.vertex.x = 0.5
    child1.mass = 0.000511
    child1.charge = -1

    child2 = model.Particle()
    child2.pdg = -11
    child2.vertex.x = 0.5
    child2.mass = 0.000511
    child2.charge = 1

    child_ids = event.add_entries('Particle', child1, child2)
    for ID in child_ids:
        event.tag_entry(ID, 'GenStable')

    parent.child.extend(child_ids)
    child1.parent.append(parent_id)
    child2.parent.append(parent_id)

    print(event)
    writer.push(event)
```

### Iterating events in a file
```python
import proio # the model does not need to be imported when reading since proio
             # is self-descriptive!

test_filename = 'test_file.proio'
n_events = 0

with proio.Reader(test_filename) as reader:
    for event in reader:
        print('========== EVENT ' + str(n_events) + ' ==========')
        print(event)
        n_events += 1

print(n_events)
```

### Event inspection by tag
```python
import proio
import proio.model.eic as model

test_filename = 'test_file.proio'
with proio.Writer(test_filename) as writer:
    event = proio.Event()

    parent = model.Particle()
    parent.pdg = 443
    parent_id = event.add_entry('Particle', parent)

    child1 = model.Particle()
    child1.pdg = 11
    child2 = model.Particle()
    child2.pdg = -11
    child_ids = event.add_entries('Particle', child1, child2)
    for ID in child_ids:
        event.tag_entry(ID, 'GenStable')

    parent.child.extend(child_ids)
    child1.parent.append(parent_id)
    child2.parent.append(parent_id)

    writer.push(event)

with proio.Reader(test_filename) as reader:
    for event in reader:
        parts = event.tagged_entries('Particle')
        print('%i particle(s)...' % len(parts))
        for i in range(0, len(parts)):
            part = event.get_entry(parts[i])
            print('%i. PDG Code: %i' % (i, part.pdg))

            print('  %i children...' % len(part.child))
            for j in range(0, len(part.child)):
                print('  %i. PDG Code: %i' % (j, event.get_entry(part.child[j]).pdg))
```