Some Useful Tools/Function for Django
Sep 17, 2015 · 3 Min Read · 1 Like · 1 Comment
This post is deprecated as its based on Django 1.6 mostly.
I am going to share some useful Django tools/functions which are very useful(were for me atleast) to get things done.
Return any model class and its properties
This method will return any model class if you have the name of the class.
from django.db import models
def get_model_description(model_name=None, return_property_list=True):
for item in models.get_models(include_auto_created=True):
if item.__name__ == model_name:
if return_property_list is True:
return item.get_trigger_properties()
else:
return item
return []
For usage, let us think of an example. Let us think, we have a class name ‘X’, we will get the class instance using it like this:
from usefultools import get_model_descriptor
model_x = get_model_descriptor(model_name='X') #will get class
model_x_objects = get_model_descriptor(model_name='X').objects.all() #will get all the objects of this class
And for its property:
from usefultools import get_model_descriptor
model_x = get_model_descriptor(model_name='X', return_property_list=True) #will get a list of properties like ['a_property','b_property']
Distance calculator
If you input latitude and longitude of two places, this function will return the distance in between them. Got help from here: http://code.activestate.com/recipes/576779-calculating-distance-between-two-geographic-points/
import math
def distance_calculator(lat1, long1, lat2, long2):
lat1, long1, lat2, long2 = float(lat1), float(long1), float(lat2), float(long2)
degrees_to_radians = math.pi/180.0
phi1 = (90.0 - lat1)*degrees_to_radians
phi2 = (90.0 - lat2)*degrees_to_radians
theta1 = long1*degrees_to_radians
theta2 = long2*degrees_to_radians
cos = (math.sin(phi1)*math.sin(phi2)*math.cos(theta1 - theta2) +
math.cos(phi1)*math.cos(phi2))
arc = math.acos( cos )
distance = arc*6378.1
return distance
It will return the distance in KM.
Dynamic relational operations
Suppose we have a sentence like: '5 is greater than 9' and check if its true. We could use eval to dynamically converty string to python but its highly not recommended. So I tried like this:
def calculate_relational_operation(lhs, rhs, operator):
get_type = type(lhs).__name__
if get_type == 'str':
rhs = str(rhs)
elif get_type == 'float':
rhs = float(rhs)
elif get_type == 'int':
rhs = int(rhs)
if operator == "==":
if lhs == rhs:
return True
return False
elif operator == "!=":
if lhs != rhs:
return True
return False
elif operator == ">":
if lhs > rhs:
return True
return False
elif operator == "<":
if lhs < rhs:
return True
return False
elif operator == ">=":
if lhs >= rhs:
return True
return False
elif operator == "<=":
if lhs == rhs:
return True
return False
elif operator == "Is":
if lhs is rhs:
return True
return False
return False
It will return True or False depending on the statement/input.
Get week list
It will return all the weeks list from last 1 year (extendable).
from isoweek import Week
def generate_week():
max_week = datetime.datetime.combine(Week.thisweek().thursday(), datetime.time(0,0))
min_week = max_week - datetime.timedelta(days=365)
_weeks = list()
while True:
_weeks.append('Week'+str(max_week.isocalendar()[1])+ ' ' +str(max_week.isocalendar()[0])))
max_week -= datetime.timedelta(days=7)
if max_week <= min_week:
break
return _weeks
#Output>> ['Week2 2015', 'Week1 2015', 'Week52 2014' ....]
Get month list
It will return last 12 month’s year and month number. Constructed using this Stack Overflow answer.
x = 12
now = time.localtime()
print([time.localtime(time.mktime((now.tm_year, now.tm_mon - n, 1, 0, 0, 0, 0, 0, 0)))[:2] for n in range(x)])
#Output>> [(2015, 2), (2015, 1), (2014, 12), (2014, 11), (2014, 10), (2014, 9), (2014, 8), (2014, 7), (2014, 6), (2014, 5), (2014, 4), (2014, 3)]
Thats it. Thanks for reading.
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