jdc 0.0.8

Dynamic classes for Jupyter/IPython notebooks.

# jdc - Jupyter Dynamic Classes

*Alex Hagen*

``jdc`` is a Jupyter magic made to solve a very specific problem: that sometimes
you want to define classes dynamically in Jupyter notebooks, and you want it to
look good. On
[Jupyter's Github](https://github.com/jupyter/notebook/issues/1243) there's a
lengthy discussion and wider view of this issue, but I've implemented a quickfix
which I think ended up looking pretty semantic. Thanks to
[Igor Sobreira](http://igorsobreira.com/2011/02/06/adding-methods-dynamically-in-python.html)
for the underlying IPython.

The example below will be most informative, but basically all ``jdc`` allows you
to do is to add a cell and define

```python
%%add_to our_class
def our_function(self, our_variable):
print our_variable
```

and that will add the method ``our_function`` to ``our_class``, whether
``our_class`` is a class, or an object with a class type.

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Example[¶](#Example){.anchor-link} {#Example}
===================================

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Below is an example on how to use `jdc`. First we have to import the
class:

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import jdc

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Then, we have to make a dummy class:

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class dog(object):
def __init__(self, name, noise):
self.name = name
self.noise = noise


rover = dog('Rover', 'ruff')
spot = dog('Spot', 'woof')

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Then, we want to add a function to that class:

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%%add_to dog
def bark(self, times=1):
saying = ('%s ' % self.noise) * times
print "%s says: %s" % (self.name, saying)

def bark2(self, times=1):
saying = ('%s ' % self.noise) * times
print "%s says: %s" % (self.name, saying)

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And now we can access that function from any method of that class.

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rover.bark(1)
spot.bark(2)

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Rover says: ruff
Spot says: woof woof

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If we want to add a function to only one object of that class, we can do
that, as well:

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%%add_to spot
def sit(self):
print '%s is now sitting' % self.name

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spot.sit()

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Spot is now sitting

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Note that the function added to a class object is only available to that
object, not all objects of that class:

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try:
rover.sit()
except AttributeError:
print "%s doesn't know that trick" % rover.name

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Rover doesn't know that trick

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And if we're writing a lot of code, we can now do that in a single cell.

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%%add_to spot
def rollover(self):
print "%s rolled over" % self.name

def highfive(self):
print "%s is trying to high five you" % self.name

def domytaxes(self):
print "%s is just showing off now" % self.name

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spot.rollover()
spot.highfive()
spot.domytaxes()

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Spot rolled over
Spot is trying to high five you
Spot is just showing off now

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Nesting functions and decorators should now work. Notice when calling
the wrapped function that we must call it by `func(self, *args)` instead
of `self.func(*args)` or `func(*args)`.

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%%add_to dog
def race(func):
def wrapper(self):
import time
t1 = time.time()
func(self)
t2 = time.time()
print "A new record time, %s finished in: " % self.name + str((t2 - t1)) + " seconds!\n"
return wrapper

@race
def race_course(self):
print "%s finished the course." % self.name

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spot.race_course()

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Spot finished the course.
A new record time, Spot finished in: 0.000334978103638 seconds!

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and that's it.

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## Installation

Right now, installation should now work through PyPI:

```bash

pip install jdc

```

Please open up an issue if it doesn't work, I'll fix it!