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+--- Thread: Understanding the module python-craigslist (/thread-5317.html)
Understanding the module python-craigslist - duccio - Sep-28-2017
HI,
I am trying to understand how the module python-craigslist works.
The __init__.py file is too long to be posted here, so I cut a simplified version to give an idea.
from six import iteritems
class CraigslistBase(object):
""" Base class for all Craiglist wrappers. """
base_filters = {
'query': {'url_key': 'query', 'value': None},
'search_titles': {'url_key': 'srchType', 'value': 'T'},
'has_image': {'url_key': 'hasPic', 'value': 1},
'posted_today': {'url_key': 'postedToday', 'value': 1},
'search_distance': {'url_key': 'search_distance', 'value': None},
'zip_code': {'url_key': 'postal', 'value': None},
}
extra_filters = {}
def __init__(self, filters=None):
self.filters = {}
for key, value in iteritems((filters or {})):
filter = (self.base_filters.get(key) or
self.extra_filters.get(key))
if filter['value'] is None:
self.filters[filter['url_key']] = value
elif isinstance(filter['value'], list):
valid_options = filter['value']
if not hasattr(value, '__iter__'):
value = [value] # Force to list
options = []
for opt in value:
options.append(valid_options.index(opt) + 1)
self.filters[filter['url_key']] = options
elif value: # Don't add filter if ...=False
self.filters[filter['url_key']] = filter['value']
class CraigslistHousing(CraigslistBase):
""" Craigslist housing wrapper. """
default_category = 'hhh'
custom_result_fields = True
extra_filters = {
'private_room': {'url_key': 'private_room', 'value': 1},
'private_bath': {'url_key': 'private_bath', 'value': 1},
'cats_ok': {'url_key': 'pets_cat', 'value': 1},
'dogs_ok': {'url_key': 'pets_dog', 'value': 1},
'min_price': {'url_key': 'min_price', 'value': None},
'max_price': {'url_key': 'max_price', 'value': None},
'min_ft2': {'url_key': 'minSqft', 'value': None},
'max_ft2': {'url_key': 'maxSqft', 'value': None},
'min_bedrooms': {'url_key': 'min_bedrooms', 'value': None},
'max_bedrooms': {'url_key': 'max_bedrooms', 'value': None},
'min_bathrooms': {'url_key': 'min_bathrooms', 'value': None},
'max_bathrooms': {'url_key': 'max_bathrooms', 'value': None},
'no_smoking': {'url_key': 'no_smoking', 'value': 1},
'is_furnished': {'url_key': 'is_furnished', 'value': 1},
'wheelchair_acccess': {'url_key': 'wheelchaccess', 'value': 1},
} The code is run as following:
ch_l = CraigslistHousing(filters={'max_price': 1200,
'private_room': True})
print(ch_l.filters)I am interested in what happens in line 28. As I understand, we pass "filters" as a dictionary through the sub-class CraigslistHousing. I'd assume the code would loop through that but, before the loop, the code sets filters = {}As far as I understand, this overrides what we passed as a parameter to the function but clearly that is not the case. Can anyone explain it to me?
Thank you
PS: Here's the link to the original module, with the full functioning code.
RE: Understanding the module python-craigslist - buran - Sep-28-2017
you need to make difference between
filters that is passed as argument when instantiate the object and self.filters which is filters attribute of the [instance of] the class.On line 28 it sets
self.filters to be empty dict and then it iterates over items in the filters that you pass when create/init the class instance and populates the self.filters. The reason - it that does need some preprocessing of the filters argument key/values
RE: Understanding the module python-craigslist - duccio - Sep-29-2017
Sure, I didn't notice they were two different variables!
Thank you