probed 0.0.8

Probed collection

Probed collections

This project is part of the Pyrustic Ecosystem.

Installation | Documentation

Overview

Sometimes you need to know when the content of a data collection has changed.

Probed is a library that exposes three classes: ProbedDict, ProbedList and ProbedSet.

These classes are containers like the built-in Python containers (dict, list, set) which they subclass but with not a twist but two twists:

• be notified when the content of your data collection changes (if you wish to be notified);
• being able to put a probe into data collection to do more than just be notified.

Let's write a script to see Probed in action:

# script.py
from probed import ProbedList


def on_change(info):
    msg = "\nThe {} operation changed the {} collection\n{}"
    print(msg.format(info.operation, info.container, info.collection))


plist = ProbedList(on_change=on_change)
plist.append("hi")
plist.insert(1, "friend")

Let's run the script:

$ python3 script.py

The append operation changed the list collection
['hi']

The insert operation changed the list collection
['hi', 'friend']

Now, let's discover what the probe feature does and how to use it:

# script.py
from probed import ProbedSet


def probe(info):
    # this probe will lower strings added to the collection
    # also, the object None isn't allowed in the collection
    if info.operation == "add":
        if info.item is None:
            info = None
        else:
            info.item = info.item.lower()
    return info


pset = ProbedSet(probe=probe)
# add items
pset.add("RED")
pset.add(None)
pset.add("Green")
# print
print(pset)  # {'red', 'green'}

In the last script, the probe was used to control the items added to the data collection.

All operations that change the contents of the built-in containers are covered by probed.

The library Shared uses Probed !

Read the modules documentation !

Installation

Probed is available on PyPI:

$ pip install probed