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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
 network(), radar() and site() objects
This notebook introduces the high-level python interface with the radar.dat and hdw.dat content.  
For more in-depth access (i.e., your own hdw.dat), look at the radInfoIO module
Step1:  Import all radars
This could be used to iterate through radars, plot them all on a map, find radars in view of specific points...
Step2:  Import a specific radar
Saves memory and time
Step3:  Import a specific radar site
Saves even more memory and time
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Python Code:
# Import radar module
%pylab inline
from davitpy.pydarn.radar import *
Explanation: network(), radar() and site() objects
This notebook introduces the high-level python interface with the radar.dat and hdw.dat content.  
For more in-depth access (i.e., your own hdw.dat), look at the radInfoIO module: 
radInfoIo?
End of explanation
radars = network()
print radars
# How to get the total number of radars
print len(radars)
print radars.nradar
# How to get a specific radar from the mountain of recorded radars
print radars.getRadarByCode("bks")
# is equivalent to...
#print radars.getRadarById(33)
#print, radars.getRadarByName("Blackstone")
# How to get a specific radar site information at a given date
from datetime import datetime
print radars.getRadarByName('Goose Bay').getSiteByDate(datetime(2011,1,4))
Explanation: Import all radars
This could be used to iterate through radars, plot them all on a map, find radars in view of specific points...
End of explanation
# How to get only one radar without getting all the other radars
rad = radar(code='bks')
print rad
Explanation: Import a specific radar
Saves memory and time
End of explanation
# How to get a site without going trhough the whole network or radar classes
print site(code='bks', dt=datetime(2010,11,17))
Explanation: Import a specific radar site
Saves even more memory and time
End of explanation
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