10.12.2019 Python

import timeit

MAX_EXPONENT = 15
NUMBER = 10

# define tests
TEST_IN = '''
found = 0
for x in needles:
    if x in haystack:
        found += 1
'''
TEST_SETS = '''
len(needles & haystack)
'''
TEST_SETS_F_LITS = '''
len(set(needles) & set(haystack))
'''

# define setups
SETUP_LISTS = '''
import random
random.seed(81)
haystack = [random.random()
            for _ in range({size})]
needles = ([random.random()
            for _ in range(500)]
           + random.sample(haystack, 500))
'''
SETUP_SETS = '''
import random
random.seed(81)
haystack = set(random.random()
            for _ in range({size}))
needles = (set(random.random()
            for _ in range(500))
           | set(random.sample(haystack, 500)))
'''

# combine tests and setups
tests = [('in_lists',        TEST_IN,          SETUP_LISTS),
         ('in_sets',         TEST_IN,          SETUP_SETS),
         ('sets',            TEST_SETS,        SETUP_SETS),
         ('sets_from_lists', TEST_SETS_F_LITS, SETUP_LISTS)]

#timeit.timeit(TEST_IN,
#              setup=SETUP_SETS.format(size=2**10),
#              number=NUMBER)

# perform tests and print results
print('{} {} {}'.format('name', 'time', 'factor'))

for n in range(10, MAX_EXPONENT+1):
    size = 2**n
    print(40*'-')
    print('size =', size)

    results = [(name,
        timeit.timeit(test, setup=setup.format(size=size), number=NUMBER))
        for name, test, setup in tests]

    t_ref = results[0][1]

    for name, t in results:
        print('{:14} {:12.4f} {:11.2f}'.format(name, t, t_ref/t))


-------------------------------------------------------------------------

>>> lambda a,b: a+b
<function <lambda> at 0x000001F58C698168>
>>> f = lambda a,b: a+b
>>> f
<function <lambda> at 0x000001F58C698288>
>>> lambda 3,4: a+b
SyntaxError: invalid syntax
>>> (lambda a,b: a+b)(12, 15)
27
>>> def stworz_inc(n):
    return (lambda x: x+n)(4)

>>> stworz_inc(3)
7
>>> stworz_inc(10)
14
>>> def stworz_inc(n):
    return lambda x: x+n

>>> f10 = stworz_inc(10)
>>> f5 = stworz_inc(5)
>>> f1 = stworz_inc(1)
>>> x = 4
>>> f10(x), f5(x), f1(x)
(14, 9, 5)
-------------------------
>>> for f in [f1,f5,f10]:
    print(f(x))
5
9
14
--------------------------
pary = [
    (3, 'trzy'),
    (1, 'jeden'),
    (2, 'dwa'),
    (4, 'cztery'),
]

>>> sorted(pary)
[(1, 'jeden'), (2, 'dwa'), (3, 'trzy'), (4, 'cztery')]
>>> pary.sort()
>>> pary
[(1, 'jeden'), (2, 'dwa'), (3, 'trzy'), (4, 'cztery')]
>>>

-----------------------
sorted(pary, key=lambda x: x[1])
[(4, 'cztery'), (2, 'dwa'), (1, 'jeden'), (3, 'trzy')]
>>> sorted(pary, key=lambda x: x[1][-1])
[(2, 'dwa'), (1, 'jeden'), (3, 'trzy'), (4, 'cztery')]
>>> sorted(pary, key=lambda x: abs(x[0]))
[(1, 'jeden'), (2, 'dwa'), (3, 'trzy'), (4, 'cztery')]