Python – Eric Lapouyade Info

Linked items to a Tree

Eric / February 15, 2018

Let’s say you receive a list of 2 linked items having a “is included in” relation. For example, you receive this list :

[('cpqswccmibrev', 'cpqswcc'),
 ('cpqswccfibredevstate', 'cpqswccfibre'),
 ('cpqswccemudev', 'cpqswcc'),
 ('cpqswccmibrevmajor', 'cpqswccmibrev'),
 ('cpqswcc', 'compaq'),
 ('cpqswccmibcondition', 'cpqswccmibrev'),
 ('cpqswccfibredevname', 'cpqswccfibre'),
 ('cpqswccfibre', 'cpqswcc'),
 ('cpqswccfibreeventdescription', 'cpqswccfibre'),
 ('cpqswccmibrevminor', 'cpqswccmibrev'),
 ('cpqswcckzpcc', 'cpqswcc')]

[('cpqswccmibrev', 'cpqswcc'),

('cpqswccfibredevstate', 'cpqswccfibre'),

('cpqswccemudev', 'cpqswcc'),

('cpqswccmibrevmajor', 'cpqswccmibrev'),

('cpqswcc', 'compaq'),

('cpqswccmibcondition', 'cpqswccmibrev'),

('cpqswccfibredevname', 'cpqswccfibre'),

('cpqswccfibre', 'cpqswcc'),

('cpqswccfibreeventdescription', 'cpqswccfibre'),

('cpqswccmibrevminor', 'cpqswccmibrev'),

('cpqswcckzpcc', 'cpqswcc')]

Here (‘cpqswcc’, ‘compaq’) means ‘cpqswcc’ is included in ‘compaq’. You may want to build a relation tree like this :

{   'compaq': {   'cpqswcc': {   'cpqswccemudev': 0,
                                 'cpqswccfibre': {   'cpqswccfibredevname': 0,
                                                     'cpqswccfibredevstate': 0,
                                                     'cpqswccfibreeventdescription': 0},
                                 'cpqswcckzpcc': 0,
                                 'cpqswccmibrev': {   'cpqswccmibcondition': 0,
                                                      'cpqswccmibrevmajor': 0,
                                                      'cpqswccmibrevminor': 0}}}}

{ 'compaq': { 'cpqswcc': { 'cpqswccemudev': 0,

'cpqswccfibre': { 'cpqswccfibredevname': 0,

'cpqswccfibredevstate': 0,

'cpqswccfibreeventdescription': 0},

'cpqswcckzpcc': 0,

'cpqswccmibrev': { 'cpqswccmibcondition': 0,

'cpqswccmibrevmajor': 0,

'cpqswccmibrevminor': 0}}}}

The cool function to do that would be the one in this code :

import pprint
pp = pprint.PrettyPrinter(indent=4)

def isincludedin_to_tree(item_list):
    out = {}
    index = {}
    for k,v in item_list:
        if v not in index and k not in index:
            out[v] = {k: 0}
            index[k] = out[v]
            index[v] = out
        elif v in index and k in index:
            if isinstance(index[v][v],int):
                index[v][v] = { k : index[k][k] }
            else:
                index[v][v][k] = index[k][k]
            to_del = index[k]
            index[k] = index[v][v]
            del to_del[k]
        elif v in index:
            dct = index[v]
            if isinstance(dct[v],int):
                dct[v] = {k: 0}
                index[k] = dct[v]
            else:
                dct[v].update({k: 0})
                index[k] = dct[v]
        else:
            dct = index[k]
            out.update({v:{k:dct[k]}})
            index[v] = out
            index[k] = out[v]
            del out[k]
    return out

in_list = [('cpqswccmibrev', 'cpqswcc'),
 ('cpqswccfibredevstate', 'cpqswccfibre'),
 ('cpqswccemudev', 'cpqswcc'),
 ('cpqswccmibrevmajor', 'cpqswccmibrev'),
 ('cpqswcc', 'compaq'),
 ('cpqswccmibcondition', 'cpqswccmibrev'),
 ('cpqswccfibredevname', 'cpqswccfibre'),
 ('cpqswccfibre', 'cpqswcc'),
 ('cpqswccfibreeventdescription', 'cpqswccfibre'),
 ('cpqswccmibrevminor', 'cpqswccmibrev'),
 ('cpqswcckzpcc', 'cpqswcc')]

out_dict = isincludedin_to_tree(in_list)

pp.pprint(out_dict)

import pprint

pp = pprint.PrettyPrinter(indent=4)

def isincludedin_to_tree(item_list):

out = {}

index = {}

for k,v in item_list:

if v not in index and k not in index:

out[v] = {k: 0}

index[k] = out[v]

index[v] = out

elif v in index and k in index:

if isinstance(index[v][v],int):

index[v][v] = { k : index[k][k] }

else:

index[v][v][k] = index[k][k]

to_del = index[k]

index[k] = index[v][v]

del to_del[k]

elif v in index:

dct = index[v]

if isinstance(dct[v],int):

dct[v] = {k: 0}

index[k] = dct[v]

else:

dct[v].update({k: 0})

index[k] = dct[v]

else:

dct = index[k]

out.update({v:{k:dct[k]}})

index[v] = out

index[k] = out[v]

del out[k]

return out

in_list = [('cpqswccmibrev', 'cpqswcc'),

('cpqswccfibredevstate', 'cpqswccfibre'),

('cpqswccemudev', 'cpqswcc'),

('cpqswccmibrevmajor', 'cpqswccmibrev'),

('cpqswcc', 'compaq'),

('cpqswccmibcondition', 'cpqswccmibrev'),

('cpqswccfibredevname', 'cpqswccfibre'),

('cpqswccfibre', 'cpqswcc'),

('cpqswccfibreeventdescription', 'cpqswccfibre'),

('cpqswccmibrevminor', 'cpqswccmibrev'),

('cpqswcckzpcc', 'cpqswcc')]

out_dict = isincludedin_to_tree(in_list)

pp.pprint(out_dict)

Python

How to get Class attributes order

Eric / January 29, 2018

Before python 3.6 it was difficult to get attributes order from a class. Let’s say, for instance, you want to create a listing class which contains columns to display :

class Column(object):
  pass

class Listing(object):
  col1 = Column()
  col2 = Column()
  col3 = Column()
  col4 = Column()
  col5 = Column()
  col6 = Column()


print( [ k for k in Listing.__dict__.keys() if '__' not in k ] )

class Column(object):

pass

class Listing(object):

col1 = Column()

col2 = Column()

col3 = Column()

col4 = Column()

col5 = Column()

col6 = Column()

print( [ k for k in Listing.__dict__.keys() if '__' not in k ] )

With python 2.7 you will get :

['col6', 'col4', 'col5', 'col2', 'col3', 'col1']

1	['col6', 'col4', 'col5', 'col2', 'col3', 'col1']

With python 3.5 you will get :

['col3', 'col1', 'col4', 'col5', 'col2', 'col6']

1	['col3', 'col1', 'col4', 'col5', 'col2', 'col6']

And finally, with python 3.6, there is no problem any more : attributes…

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Python

How to dynamically create a class with some mixins

Eric / January 24, 2018

Let’s say you want to create a class that includes mixins having names that are known at execution time only, you would do some thing like this :

class_with_mixins = type("my_class_name", tuple(mixins_classes+[BaseClass]), {})

1	class_with_mixins = type("my_class_name", tuple(mixins_classes+[BaseClass]), {})

To get mixins_classes, juste use importlib to get mixins classes from names. A function that would create an instance of such a dynamic class would be something like this :

from importlib import import_module

def get_instance_with_mixins(plugin_class_name,mixins_name,base_class,*args,**kwargs):
    mixins_classes = [ import_module(m) for m in mixins_name ]
    cls = type(plugin_class_name, tuple(mixins_classes+[base_class]), {})
    instance = cls(*args,**kwargs)
    return instance

from importlib import import_module

def get_instance_with_mixins(plugin_class_name,mixins_name,base_class,*args,**kwargs):

mixins_classes = [ import_module(m) for m in mixins_name ]

cls = type(plugin_class_name, tuple(mixins_classes+[base_class]), {})

instance = cls(*args,**kwargs)

return instance

…

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Django

How to configure a Django social authentication with django-allauth and reCaptcha

Eric / December 28, 2017

You want to create a Django website with social authentication, that is with such a login form : and still having the possibility to create a local account if the user wants to, such a sign-up form would look like this : Note the captcha to check the user is not a robot. Of course, you want all email checking…

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Python

Hello world!

Eric / December 27, 2017

#!/usr/bin/env python3.6

print('Hello world !')

#!/usr/bin/env python3.6

print('Hello world !')

… my first post