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ͬ͟ͱΘ͔Δ
Python
hakobe
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ൃදͷഎܠ
• ͍ΖΜͳݴޠΛదࡐదॴͰ͍͜ͳ͍ͨ͠
ͷͰ͢Ͷ
• Pythonʹ͍͕͋ΔͷͰ͑ΔΑ͏ʹͳͬ
ͯΔͱศརͦ͏
• ͬ͘͟ΓௐͨͷͰͬ͘͟Γհ͠·͢
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Python (ͬ͘͟Γ)
• ൚༻εΫϦϓτݴޠ
• ΠϯσϯτͰΞϨ͢Δͭ
• 2ͱ3͕͋Δ
• ࠷ۙΘΓͱਓؾ͕͕͋ͬͯΔ
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Python
class Blog():
def __init__(self, id, owner_id, title):
self.id = id
self.owner_id = owner_id
self.title = title
def is_owned_by(self, user):
return user.id == self.owner_id
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ࠓͷΰʔϧ:
Pythonͷงғؾ͕ͬ͟ͱΘ͔Δ
˒ ։ൃڥ
˒ Web։ൃ
˒ σʔλੳ
˒ ݴޠͷਐԽ
˒ ίϛϡχςΟ
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։ൃڥ
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Python 2? 3?
• Python3 Λ͑OK
• ۙϥΠϒϥϦἧ͖ͬͯͨ
• Python2ܥ2020Ͱऴྃ
• 2.7ܥ͕࠷ޙͷϦϦʔε
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Python3 Unicodeจࣈྻ
1. ৗʹ use utf8; ͞ΕΔΑ͏ʹͳͬͨ(Perl
2. จࣈྻͱόΠτྻΛ·ͥΔͱྫ֎ʹͳΔ
• ݕࡧΩʔϫʔυ: “python3 unicode ͳͥ”
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Python3ͷจࣈྻͷߟ͑ํ
• ೖྗΛdecode/ग़ྗΛencode(ͬͯΔ
ͭ!
# 外部からの入力はバイト列
in_bytes = b'\xf0\x9f\x8d\xa3'
string = in_bytes.decode('utf-8')
# バイト列にして外部に出力
out_bytes = string.encode('utf-8')
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खݩڥͷߏங
• ݕࡧΩʔϫʔυ: “Python yamaguchi 2017”
• ʙ؆୯3εςοϓʙ
• pyenvͰॲཧܥΛ͍ΕΔ
• python -m venv ͰڥΓସ͑Δ
• pip ͰϥΠϒϥϦΛΠϯετʔϧ͢Δ
ͿͬͪΌ͚ॾઆ͋Δ͚ͲखݩͰ͜ΕͰշద
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ϥΠϒϥϦ
• ඪ४ϥΠϒϥϦ
• Battery Included ํࣜͰॆ࣮
• https://docs.python.jp/3/library/
• CPANతͳͭ = PyPI
• ඪ४ͷpip ίϚϯυͰΠϯετʔϧͰ͖Δ
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PyPI
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ΤσΟλ
• ͍͍ͩͨPythonαϙʔτ͕͋ͬͯ҆৺
• ྑ͍IDE͋Δ: PyCharm
• ࠷ۙࣗVisual Studio CodeΛͬͯΔ
• linterิ͕͙͑ͯ͢ศར
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Linter
• flake8Λ͍͍͑ͩͨOK
• ͨΒLinterతϥΠϒϥϦ͕ଟ͍
• pycodestyle, pydocstyle, pyflake, flake8,
hacking …
• autopep8 ॻ͖͑ͯ͘ΕΔͭ͋Δ
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flake8
• pycodestyle + pyflake
> flake8 enjoy.py
enjoy.py:1:1: F401 'os' imported but unused
enjoy.py:3:1: E302 expected 2 blank lines, found 1
enjoy.py:4:5: F841 local variable 'i' is assigned to but never used
enjoy.py:9:5: E303 too many blank lines (2)
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Test
VOJUUFTU ඪ४ఴɺඞཁे
QZUFTU ׆ൃɺΑ͘ΘΕͯΔɺQPXFSBTTFSU
OPTF ੲ͍͕͋ͬͨΒ͍͠
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py.test
def inc(x):
return x + 1
def test_answer():
assert inc(3) == 5
def test_misc():
assert [1,2,3,4], [1,2,3,4]
assert isinstance('hello', str)
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pytest ͷ࣮ߦ݁Ռ
================== FAILURES ===================
_________________ test_answer _________________
def test_answer():
> assert inc(3) == 5
E assert 4 == 5
E + where 4 = inc(3)
test_pyt.py:5: AssertionError
===== 1 failed, 1 passed in 0.06 seconds ======
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TestࢧԉϥΠϒϥϦ
• freezegun = Test::TimeΈ͍ͨͳͭ
from freezegun import freeze_time
import datetime
def test_time():
with freeze_time("2020-06-06"):
assert datetime.datetime.now() == \
datetime.datetime(2020, 6, 6)
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Web։ൃ
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WebϑϨʔϜϫʔΫ
'MBTL "NPOతͳܰྔλΠϓ
%KBOHP 3BJMTతͳΜͰ͍ΓϦονλΠϓ
1ZSBNJE దͳ͓ͯͳ͠
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Flask
from flask import (Flask, request, redirect)
web = Flask(__name__)
@web.route('//edit', methods=['POST'])
def edit():
title = request.form['title']
body = request.form['body']
entry = create(title, body)
return redirect('/entry/' + entry.id)
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WSGI
• αʔόͱΞϓϦέʔγϣϯؒͷϓϩτίϧ
• PSGIͷܑ͓͞Μ
def app(environ, start_response):
start_response(
'200 OK', [('Content-Type', 'text/plain')]
)
yield b'Hello World\n’
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HTTPαʔό
• جຊ prefork worker model
• uWSGIthread͑ΔͬΆ͍?
V84(* ࠷ۙྲྀߦΓͰଟػೳ
(VOJDPSO 3VCZͷΞϨ༝དྷͰγϯϓϧ
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σʔλϕʔε
• DB͝ͱͷϥΠϒϥϦ: e.g. mysqlclient
• APIPEP 249Ͱඪ४Խ (DBI+DBD)
import MySQLdb
conn = MySQLdb.connect(db='enjoy')
with conn.cursor() as cursor:
cursor.execute('SELECT UUID_SHORT() as uuid')
print(cursor.fetchone().get('uuid'))
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ORM
• DBϥΠϒϥϦΛͦͷ··͏͘Β͍Ͱ
42-"MDIFNZ ਓؾɻΫΤϦϏϧμతͳ͍ํ
%KBOHP03. %KBOHP͏ͳΒ
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ബ͍Web AppͷߏΛࢼͯ͠Έͨ
• hakobe/hakoblog-python
• ബ͍WebϑϨʔϜϫʔΫ (Flask)
• ORMͳ͠ (mysqlclientΛʹ͏)
• ServiceϨΠϠ
• ςϯϓϨʔτΤϯδϯ Jinja2
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ORMΘͣʹૉʹ͍ͬͯ͘
class BlogLoader():
@classmethod
def find_by_id(cls, db, blog_id):
with db.cursor() as cursor:
row = cursor.execute('''
SELECT id, owner_id, title
FROM blog
WHERE id = %s''',
(blog_id, )
).fetchone()
return Blog(**row)
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ϔϧύΛఆ͍͍ٛͯ͠ײ͡ʹςετ
def test_find_by_id():
"EntryLoader.find_by_id() can find a entry by id"
db = DB()
entry = create_entry()
found_entry = EntryLoader.find_by_id(db, entry.id)
assert isinstance(found_entry, Entry)
assert found_entry.id == entry.id
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σʔλղੳ
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σʔλղੳϥΠϒϥϦ
• ͱʹ͔͘ॆ࣮ͯ͠Δ ɹ ͷΩϥʔίϯςϯπ
• numpy
• scipy
• scikit-learn
• pandas
• matplotlib
• Jupyter notebook
• σʔλղੳ͍ͨ͠ਓ͕ू·͍ͬͯͯ॥
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Numpy
• ΊͬͪΌߴʹߦྻԋࢉͰ͖Δͭ
• ߦྻͷσʔλܕΛ౷Ұ͢Δ͜ͱͰC
FortranͰߴʹԋࢉՄೳʹͯ͠Δ
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Numpy
import numpy as np
m1 = np.array([
[1, 2, 3],
[4, 5, 6],
])
m2 = np.array([
[ 7, 8, 9],
[10, 11, 12],
])
m1.dot(m2.T)
np.zeros([2, 3])
# array([[ 0., 0., 0.],
# [ 0., 0., 0.]])
np.identity(2)
# array([[ 1., 0.],
# [ 0., 1.]])
np.arange(10).reshape(2,5)
# array([[0, 1, 2, 3, 4],
# [5, 6, 7, 8, 9]])
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Scipy
• NumpyϕʔεͷศརͳՊֶܭࢉάοζू
• ౷ܭͱ͔ઢܗͱ͔৴߸ॲཧͱ͔??
• ౷ܭάοζABςετͷݕఆͱ͔ʹ͑Δ
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Scipy
• ࢀߟ: A/Bςετʹ༻͍ΒΕΕΔ౷ܭతݕఆ
ख๏ʢϩδοΫʣͷ·ͱΊˍൺֱ
import scipy
import scipy.stats
data = [
# click, access
[ 150, 500120 ], # A
[ 70, 320050 ], # B
]
chi2, p, dof, expected = scipy.stats.chi2_contingency(data)
print(p) # 0.0339
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scikit-learn
• σʔλੳ/σʔλϚΠχϯά ϥΠϒϥϦू
• ධՁͷͨΊͷศརάοζ
• ͰػցֶशΤϯδχΞͷؾʹͳΕΔ
from sklearn import svm
svc = svm.SVC()
svc.fit(X, y)
svc.predict(Xtest)
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pandas
• σʔλղੳϥΠϒϥϦ
• ϝϞϦ্ͷσʔλʹରͯ͠SQLΈ͍ͨʹ
σʔλΛϑΟϧλͨ͠Γूͨ͠ΓͰ͖Δ
• ௐࠪܥͷλεΫͰศར͕ߴ͍
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matplotlib
• σϑΝΫτͷάϥϑඳըϥΠϒϥϦ
• ͍͍ͩͨͳΜͰͰ͖ͯศར
• API͕Ή͍ͣͷͰସϥΠϒϥϦ͕ຄڵ͍ͯ͠
Δͱ͔
• ݕࡧΩʔϫʔυ: “matplotlib alternative”
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Jupyter notebook
• REPLͷ͓Խ͚(ݩIPython)
• ίʔυΛ࣮ߦͨ͠Γ࣮ߦ݁ՌΛදࣔͨ͠Γ
આ໌Λॻ͍ͨΓͰ͖ΔWebΞϓϦ
• ΊͪΌͪ͘Όࢼߦࡨޡ͍͢͠
• ͳΊ͚ͯͨͲ࣮ࡍ͔ͭ͏ͱ͛͢ʔࢼߦࡨޡ͠
͍͢…
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ݴޠͷਐԽ
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ܕΞϊςʔγϣϯ
• ؔมͷܕΛ෦తʹهड़Ͱ͖Δ
• GenericsStructual subtyping
• ݴޠػೳͱͯ͠ΞϊςʔγϣϯͷΈ
• ͋͘·Ͱಈతܕ͚͕ओ
• Smart::Argsͷ͍͍ͭ͘Β͍
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ࣗ࡞filterؔͷܕ͚
from typing import List, Callable, TypeVar
T = TypeVar('T')
def even(n: int) -> bool:
return n % 2 == 0
def filter(l: List[T], f: Callable[[T], bool]) -> List[T]:
result: List[T] = []
for e in l:
if f(e):
result.append(e)
return result
filter(['a', 'b', 'c'], even)
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mypy
• ܕΞϊςʔγϣϯΛ͏ܕνΣοΧʔ࣮
> mypy filter.py
filter.py:14: error: Argument 2 to "filter" has
incompatible type Callable[[int], bool]; expected
Callable[[str], bool]
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typeshed
• TypeScriptͷDefinitelyTypedΈ͍ͨͳ
ܕఆٛϦϙδτϦ
• .pyi ͱ͍͏֦ுࢠͰఆٛΛ͚ͩΛಡΈࠐΉ
Έ͕͋Δ
• https://github.com/python/typeshed
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asyncio
• ࠷ۙ͑Δඪ४ϥΠϒϥϦ (Python 3.4 ~
• ͋ΔඇಉظϥΠϒϥϦΛ౷Ұ
• ཁAnyEvent(Perl
• ੜϥΠϒϥϦग़͖ͯͯΔ: e.g. aiohttp
• ߏจʹΈࠐ·Εͨ (Python 3.6 ~
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asyncio ͱ async/await ߏจ
import aiohttp
import asyncio
async def fetch(session, url):
with aiohttp.Timeout(10, loop=session.loop):
async with session.get(url) as response:
return await response.text()
async def main(loop):
async with aiohttp.ClientSession(loop=loop) as session:
html = await fetch(session, 'http://python.org')
loop = asyncio.get_event_loop()
loop.run_until_complete(main(loop))
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ίϛϡχςΟ
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ίϛϡχςΟ
• ࣮͋Μ·ΓΒͳ͍… ڭ͍͑ͯͩ͘͞ʂ
• PyCon ͍͢͝Γ্͕ͬͯ·͢Ͷʂʂ
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ΘΕͯΔ҆৺ײ
• اۀ
• fastly/Google/redhat/Microsoft ͳͲ..
• ࠷৽ٕज़/اۀϥΠϒϥϦ
• AWS/Google/Swaggerͱ͔..
• ڭҭ
• Raspberry Pi
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·ͱΊ
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·ͱΊ
• PythonงғؾΛͬ͘͟Γհ
• ݁ہPythonͲ͏ͳΜ?
•
ศརͳ໘Ͱ͍ͬͯͬͨΒ͑͑ΜͪΌ͏
• ͍ΖΜͳ͜ͱ͕Ͱ͖ΔΑ͏ʹɺPython
͍͜ͳͤΔͱྑ͍Ͱ͢Ͷʂ