2018-04-14 开胃学习Python系列 - Lambda

Lambda and List Comprehensions

对lambda这个内容，我一直也是能看到，但是没有总结过，今天顺便把这个部分内容也总结一下。

my_function = lambda a, b, c : a + b
my_function(1, 2, 3)
>>> 3

people = ['Dr. C Brooks', 'Dr. K Collins-Thompson', 'Dr. VG Vydiswaran', 'Dr. D Romero']

def split_title_and_name(person):
    return person.split()[0] + ' ' + person.split()[-1]

#option 1
for person in people:
    print(split_title_and_name(person) == (lambda x: x.split()[0] + ' ' + x.split()[-1])(person))

#option 2
list(map(split_title_and_name, people)) 
== list(map(lambda x: x.split()[0] + ' ' + x.split()[-1], people))
# 输出都是true

顺便讲一个 List Comprehensions

def times_tables():
    lst = []
    for i in range(10):
        for j in range (10):
            lst.append(i*j)
    return lst

times_tables() == [j*i for i in range(10) for j in range(10)]

lowercase = 'abcdefghijklmnopqrstuvwxyz'
digits = '0123456789'
correct_answer = [a+b+c+d for a in lowercase for b in lowercase for c in digits for d in digits]
correct_answer[:50] # Display first 50 ids