'''
dictionarysorting.py -- examples of sortinng dictionaries by key and value.

Jeff Ondich, 30 Jan 2008
'''


print '============= a dictionary, its items, and its keys ==============='
theDictionary = {'goat':5, 'zebu':9, 'kudu':9, 'moose':27, 'aardvark':9}
print "theDictionary:", theDictionary
print "theDictionary.items():", theDictionary.items()
print "theDictionary keys():", theDictionary.keys()
print

print '============= a dictionary\'s keys & values, sorted by key ==============='
keys = theDictionary.keys()
keys.sort()
for key in keys:
    print key, theDictionary[key]
print


print '============= a dictionary\'s keys & values, sorted by value ==============='
print '=============    version 1, using the "sorted" function and  ==============='
print '=============    default comparison function for the values  ==============='
for key in sorted(theDictionary, key=theDictionary.get, reverse=True):
    print key, theDictionary[key]
print

print '============= a dictionary\'s keys & values, sorted by value ==============='
print '=============    version 2, using a global dictionary and a ================'
print '=============    custom comparison function                 ================'
def valueCmp(a, b):
    valueComparison = cmp(theDictionary[b], theDictionary[a])
    if valueComparison == 0:
        return cmp(a, b)
    else:
        return valueComparison

keys = theDictionary.keys()
keys.sort(valueCmp)
for key in keys:
    print key, theDictionary[key]
print


print '============= a dictionary\'s keys & values, sorted by value ==============='
print '=============    version 3, using a locally defined custom  ==============='
print '=============    comparison function                        ==============='

def getKeysSortedByValue(theDict):
    def valCmp(a, b):
        valueComparison = cmp(theDictionary[b], theDictionary[a])
        if valueComparison == 0:
            return cmp(a, b)
        else:
            return valueComparison

    keys = theDict.keys()
    keys.sort(valCmp)
    return keys

sortedKeys = getKeysSortedByValue(theDictionary)
for key in sortedKeys:
    print key, theDictionary[key]
print


print '============= a dictionary\'s keys & values, sorted by value ==============='
print '=============    version 3, using list comprehensions       ==============='
items = theDictionary.items()

items = [(v, k) for (k, v) in items]
items.sort()
items.reverse()
items = [(k, v) for (v, k) in items]

for (k, v) in items:
    print k, v