17 - Dictionaries III - counting things.ipynb

Kernel: Python 3 (system-wide)

Exercise 17.1

A student field trip to Madagascar resulted in the sightings in the following individual lemurs.

1. Create a dictionary of the number of sightings of each lemur species.

2. Print out each species name and its number of sightings in descending order of sightings.

lemurs = ['White-headed lemur', 'Gray-headed lemur', 'Common brown lemur', 'Collared brown lemur', 'Red lemur', 'Collared brown lemur', 'Red-fronted lemur', 'Red-bellied lemur', 'Collared brown lemur', 'Crowned lemur', 'Red lemur', 'Crowned lemur', 'Blue-eyed black lemur', 'Common brown lemur', 'Mongoose lemur', 'Common brown lemur', "Sanford's brown lemur", 'White-headed lemur', 'Black lemur', 'Mongoose lemur', 'Red-bellied lemur', 'Red-fronted lemur', 'Blue-eyed black lemur', 'Collared brown lemur', 'Blue-eyed black lemur', 'White-headed lemur', 'Red lemur', 'Red-bellied lemur', 'Gray-headed lemur', 'Red-bellied lemur', 'Red lemur', 'Common brown lemur', 'Mongoose lemur', 'Red lemur', 'Common brown lemur', "Sanford's brown lemur"]

sightings = {}

for lemur in lemurs:
    if lemur not in sightings:
        sightings[lemur] = 1
    else:
        sightings[lemur] += 1

for species, count in sorted(sightings.items(), reverse=True, key=lambda kv: kv[1]):
    print( f'{species}\t{count}')

Common brown lemur	5
Red lemur	5
Collared brown lemur	4
Red-bellied lemur	4
White-headed lemur	3
Blue-eyed black lemur	3
Mongoose lemur	3
Gray-headed lemur	2
Red-fronted lemur	2
Crowned lemur	2
Sanford's brown lemur	2
Black lemur	1