'''
Created on Nov 2, 2014

@author: rodger
'''
# dictionary of schools and how many students at an event
# are from each school

d = {'duke':30, 'unc':50, 'ncsu':40}

print "d.values()", d.values()
print "d.keys()", d.keys()
d['duke'] = 80
d.update({'ecu':40, 'uncc':70})
print "d.values()", d.values()

# what is the difference between these 3?

print "d.items()", d.items()
print "d.iteritems()", d.iteritems()
print "d", d

# problem - using the dictionary from above, write Python code 
# to determine how many schools have more than 40 attendees?


count = len([key for key in d if d[key] > 40])

for key in d:
    if key > 40:
        count += 1
        
for item in d.values():
    if item > 40:
        count += 1
        
for (k,v) in d.iteritems():
    if v>40:
        count += 1


print "Number of schools with more than 40 attendees is ", count


# problem - Using the dictionary from above, write python code to determine 
# which schools have more than 40 attendees - give a list

schools = [key for key in d if d[key] > 40]

for (k,v) in d.iteritems():
    if v>40:
        schools.append(k)

print "Number of schools with more than 40 attendees is ", schools  


# problem -  Create a new dictionary mapping attendance numbers to list of schools
# with that attendance number

d2 = {}

for (key, value) in d.iteritems():
    if value in d2:
        d2[value].append(key)
    else:
        d2[value] = [key]

print d2



# problem create a new dictionary mapping groups of 50 attendees 0-49, 50-99, etc
d3 = {}
for (key, value) in d.iteritems():
    value =value/50 * 50
    if value in d3:
        d3[value].append(key)
    else:
        d3[value] = [key]


print d3