Map, Filter, Reduce

Lambda function

Map

numbers = [1, 2, 3]

def double():
    return a * 2

# result = map(double, nubmers)
result = map(lambda a : a * 2, nubmers)
print(list(result)) # [2, 4, 6]

Filter

numbers = [1, 2, 3]

def isEvent(n):
    return n % 2 == 0

# result = map(double, nubmers)
result = filter(lambda n : n % 2 == 0, nubmers)
print(list(result)) # [2]

Reduce

from functools import reduce

expenses = [
    ('Dinner', 80),
    ('Car repair', 120)
]

sum = 0
for expense in expenses:
    sum += expense[1]
print(sum) # 200

sum2 = reduce(lambda a, b : a[1] + b[1], expenses) # 200