Python¶

git --version

git clone https://github.com/pyenv/pyenv.git ~/.pyenv
sudo yum install -y gcc openssl11 openssl11-devel bzip2-devel ncurses-devel libffi-devel readline-devel sqlite-devel.x86_64 xz-devel

export PATH="$HOME/.pyenv/bin:$PATH"
eval "$(pyenv init -)"

source ~/.bashrc

pyenv --version

pyenv install -l

pyenv install 3.11.7

pyenv versions

pyenv global 3.11.7

python -V

brew install asdf

asdf list all python

asdf plugin list all | grep python

asdf plugin add python https://github.com/danhper/asdf-python.git

asdf plugin list

asdf list all python

asdf install python <version>

asdf global python <version>
asdf local python <version>

asdf uninstall python <version>

brew install python@3.8

python3.8 --version

python -V

python -m venv .venv

source .venv/bin/activate

deactivate

$ brew update && brew upgrade
$ brew install pyenv
$ echo 'export PATH="$HOME/.pyenv/bin:$PATH"' >> ~/.bash_profile
$ echo 'eval "$(pyenv init -)"' >> ~/.bash_profile
$ exec $SHELL -l
$ pyenv install -l | grep anaconda # Check the newest version
$ pyenv install anaconda3-4.1.0    # Input the newest
$ pyenv global anaconda3-4.1.0     # Input the newest
$ python --version

$ cd some_directory # 適当なディレクトリに移動
$ jupyter notebook

%matplotlib nbagg

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

fig = plt.figure()
x = np.arange(0, 10, 0.1)

ims = []
for a in range(50):
    y = np.sin(x - a)
    im = plt.plot(x, y, "r")
    ims.append(im)

ani = animation.ArtistAnimation(fig, ims)
plt.show()

%matplotlib inline
import matplotlib.pyplot as plt

<!-- 距離の変動範囲 -->
r = range(100, 1001, 20)
<!-- 重力定数 -->
G = 6.674*(10**-11)
<!-- 質量 -->
m1 = 0.5
m2 = 1.5
<!-- 重力 -->
F = [G * (m1 * m2) / (dist ** 2) for dist in r]

plt.plot(r, F, marker='o')
<!-- Jupyter 上日本語が文字化けするようなので英語で書いた -->
plt.xlabel('Distance')
plt.ylabel('Newton gravitational force')
plt.title('A graph for the inverse square law')
plt.show()

v0_list = [20, 40, 60]
theta = 45
tragectories = []

def frange(start, final, interval):
    numbers = []
    # float だと range が使えないのでこの処理
    while start < final:
        numbers.append(start)
        start = start + interval

    return numbers

def get_trajectory(v0, theta):
    # 重力定数の定義
    g = 9.8

    # 入力の角度をラジアンに変換
    theta = math.radians(theta)

    # 着地までの時間の計算
    t_flight = 2 * v0 * math.sin(theta) / g

    # 着地時間までの時間リスト: dt 刻み
    dt = 0.001
    intervals = frange(0, t_flight, dt)

    # x, y 座標の計算
    x = []
    y = []
    for t in intervals:
        x.append(v0*math.cos(theta)*t)
        y.append(v0*math.sin(theta)*t - 0.5*g*t*t)

    return (x,y)

for v0 in v0_list:
    tragectories.append(get_trajectory(v0, theta))

<!-- Add a legend and show the graph -->
plt.plot(tragectories[0][0], tragectories[0][1],
         tragectories[1][0], tragectories[1][1],
         tragectories[2][0], tragectories[2][1])
plt.legend(['20', '40', '60'])
plt.show()

$ cd some_directory
$ jupyter notebook

 # まずは Hello, World! から
print("Hello, World!") # Jupyter 上で入力するとわかるが括弧やクオートが自動で両方入る

Hello, World!

 # 計算もできる

 # かけ算
print(2*2)     # 演算子の前後は空けなくてもいい

 # 割り算
print(5 / 2)   # 演算子の前後は空けてもいい

 # 切り捨て割り算
print(5 // 3)

 # あまり
print(5 % 3)

 # a の b 乗
print(5 ** 3)

4
2.5
1
2
125

 # 文字列のエスケープ
print("Hello \"world\"")             #  ダブルクオートでくくると文字列の中のダブルクオートをエスケープする必要あり
print("A list:\n* item 1\n* item 2") # \n は改行
print("C:\\path\\on\\windows")       # バックスラッシュ自体のエスケープ
print(r"C:\path\on\windows")         # r"" は生リテラル (raw literal)

Hello "world"
A list:
* item 1
* item 2
C:\path\on\windows
C:\path\on\windows

items = [3, 4, 5, 7, 6]
print(items)
print(len(items)) # リストの長さ
print(items[0])   # リストの要素を取得: 0 始まり
print(items[-1])  # マイナスにすると後ろから数えて取得
print(items[0:4]) # 複数要素を一気に取得: 第2引数の扱いに注意
items.append(8)   # 要素追加：破壊的に追加
print(items)

print("\nrange の出力") # Python3 ではリストではなくイテレータで返る
print(range(10))
print(range(1, 11))
print(range(0, 30, 5))
print(range(0, 10, 3))
print(range(0, -10, -1))
print(range(0))
print(range(1, 0))

<!-- リストを操作する関数 -->
print(sum(items))

mytuple = (1, 2, 3)
print(mytuple)
print(mytuple[0])

 # 辞書: キーと値のペア
mydict = {'a': 1, 'b': 2, 'c': 3}
print('a:', mydict['a'])
 # キーのリストを取得
print(mydict.keys())
 # 値のリストを取得
print(mydict.values())

 # 集合: 数学の集合と同じで重複は排除
myset = set([1, 2, 3, 2, 1])
print(myset)

(1, 2, 3)
1
a: 1
dict_keys(['c', 'a', 'b'])
dict_values([3, 1, 2])
{1, 2, 3}

a = [5,6,7,8,9]

<!-- 要素だけ取る -->
for x in a:
    print(x)

print("\nenumerate の出力")
<!-- キーと値を両方取得 -->
for k, v in enumerate(a):
    print(k, v)

5
6
7
8
9

enumerate の出力
0 5
1 6
2 7
3 8
4 9

a = [5,6,7,8,9]
b = [x**2 for x in a if x % 2 == 0] # 偶数だけ取得してさらに 2 乗する
print(b)

[36, 64]

a = [1,2,3]
for x in a:
    if x % 3 == 1:
        print("3 で割って余り 1")
        print(x)
    elif x % 3 == 2: # elif という気持ち悪い記法
        print("3 で割って余り 2")
        print(x)
    else:
        print("3 で割り切れる")
        print(x)

3 で割って余り 1
1
3 で割って余り 2
2
3 で割り切れる
3

def is_even(number):
    """Return whether an integer is even or not.""" # 3 つのクオートは複数行コメント
    return number % 2 == 0

print(is_even(1))
print(is_even(2))
print(is_even(3))
print(is_even(4))

False
True
False
True

$ ipython

%pwd # 以下の結果は私の環境で実行した場合の結果: 人によって変わる

'/Users/phasetr/codes/mathcodes/jupyter'

%ls -l

total 600
-rw-r--r--  1 phasetr  staff   35589  8 17 22:37 fundamentals.ipynb
-rw-r--r--  1 phasetr  staff    5987  8 14 20:15 math_simple_calculation.ipynb
-rw-r--r--  1 phasetr  staff  260296  8 17 22:38 math_simple_graph.ipynb

files = !ls -1 -S | grep test # ! をつけるとコマンド実行してくれる
print(files)

['test1', 'test2', 'test3']

 # IPython では _ で前回の出力が取れる
%pwd
print(_*2)

/Users/phasetr/codes/mathcodes/jupyter/Users/phasetr/codes/mathcodes/jupyter

#%%script ghci
#putStrLn "Hello, World"

GHCi, version 8.0.1: http://www.haskell.org/ghc/  :? for help
Prelude> Hello, World
Prelude> Leaving GHCi.

%%writefile myfile.txt
Hello world!

Overwriting myfile.txt

<!-- 前のセルからの続き -->
!more myfile.txt

Hello world!
[?1l>

<!-- 前のセルからの続き -->
!rm myfile.txt
!ls -l

rm: myfile.txt: No such file or directory
total 32
-rw-r--r--@ 1 phasetr  staff  16035  8 13 21:35 fundamentals.ipynb
-rw-r--r--@ 1 phasetr  staff      0  8 13 21:09 test1
-rw-r--r--@ 1 phasetr  staff      0  8 13 21:09 test2
-rw-r--r--@ 1 phasetr  staff      0  8 13 21:09 test3

!head -n5 t # ここで tab を押すと補完候補が出る: Jupyter 上でも出る。

<!-- GUI 系のことだってできてしまう -->
from IPython.display import YouTubeVideo
YouTubeVideo('AyJI5XyMQ9M')

    <iframe
        width="400"
        height="300"
        src="https://www.youtube.com/embed/AyJI5XyMQ9M"
        frameborder="0"
        allowfullscreen
    ></iframe>

from ipywidgets import interact
@interact(x=(0, 10))
def square(x):
    print("The square of %d is %d." % (x, x**2))

The square of 5 is 25.

<!-- 準備のためにディレクトリ・ファイル作成 -->
#!mkdir subdir
!cd subdir; touch test1.txt test2.txt test3.txt test1.org test2.org
!cd subdir; ls -l

total 0
-rw-r--r--  1 phasetr  staff  0  8 14 12:56 test1.org
-rw-r--r--@ 1 phasetr  staff  0  8 14 12:56 test1.txt
-rw-r--r--  1 phasetr  staff  0  8 14 12:56 test2.org
-rw-r--r--@ 1 phasetr  staff  0  8 14 12:56 test2.txt
-rw-r--r--  1 phasetr  staff  0  8 13 23:16 test3.org
-rw-r--r--@ 1 phasetr  staff  0  8 14 12:56 test3.txt

import networkx
<!-- 変数名の後に ? をつけるとヘルプ的なものが出る -->
networkx.Graph?
<!-- 他にも %pdef, %pdoc, %psource, %pfile などがある -->

%%writefile filelist.py
<!-- coding: utf-8 -->
import sys
import os
<!-- コマンドライン呼び出しの第 1 引数として検索するディレクトリを指定 -->
if len(sys.argv) > 1:
    directory = sys.argv[1]

<!-- 該当ディレクトリ内の全てのディレクトリをリストアップ -->
files = os.listdir(directory)
<!-- 拡張子を切り捨ててファイル名だけ取り出す -->
identifiers = [file.split('.')[0] for file in files]
<!-- set で重複を取り除いてソートする -->
names = sorted(set(identifiers))

Overwriting filelist.py

<!-- スクリプト実行 -->
%run filelist.py subdir
print(names)

['test1', 'test2', 'test3']

from sympy import *
from IPython.display import display
init_printing(use_unicode=True)

 * シンボル定義
x = Symbol('x')
y = Symbol('y')

 # display で出力すると mathjax 連携してくれて素敵
display(x + y + x - 4 * y)

a = Integral(cos(x)*exp(x), x)
display(Eq(a, a.doit()))

import sympy
display(sympy.sqrt(3))

 # 勝手に計算やってくれるので素敵
display(sympy.sqrt(8))

from sympy import symbols
x, y = symbols('x y')
expr = x + 2*y
display(expr)
display(expr + 1)
display(expr - x)
display(x*expr)

from sympy import expand, factor
expanded_expr = expand(x*expr)
display(expanded_expr)
display(factor(expanded_expr))

from sympy import *
x, t, z, nu = symbols('x t z nu')

print('計算: diff(sin(x)*exp(x), x)')
display(diff(sin(x)*exp(x), x))

print('計算: integrate(exp(x)*sin(x) + exp(x)*cos(x), x)')
display(integrate(exp(x)*sin(x) + exp(x)*cos(x), x))

print('計算: integrate(sin(x**2), (x, -oo, oo))')
display(integrate(sin(x**2), (x, -oo, oo)))

print('計算: limit(sin(x)/x, x, 0)')
display(limit(sin(x)/x, x, 0))

print('計算: solve(x**2 - 2, x)')
display(solve(x**2 - 2, x))

print('微分方程式の解: y" - y = e ** t')
f = Function('f')
display(dsolve(Eq(f(t).diff(t, t) - f(t), exp(t)), f(t)))

print('行列の固有値: Matrix([[1, 2], [2, 2]]).eigenvals()')
display(Matrix([[1, 2], [2, 2]]).eigenvals())

print('ベッセル関数を球ベッセル関数で書く')
print('besselj(nu, z).rewrite(jn)')
display(besselj(nu, z).rewrite(jn))

print('LaTeX にする')
print('latex(Integral(cos(x)**2, (x, 0, pi)))')
display(latex(Integral(cos(x)**2, (x, 0, pi))))

計算: diff(sin(x)*exp(x), x)

計算: integrate(exp(x)*sin(x) + exp(x)*cos(x), x)

計算: integrate(sin(x**2), (x, -oo, oo))

計算: limit(sin(x)/x, x, 0)

計算: solve(x**2 - 2, x)

微分方程式の解: y" - y = e ** t

行列の固有値: Matrix([[1, 2], [2, 2]]).eigenvals()

ベッセル関数を球ベッセル関数で書く
besselj(nu, z).rewrite(jn)

LaTeX にする
latex(Integral(cos(x)**2, (x, 0, pi)))

'\\int_{0}^{\\pi} \\cos^{2}{\\left (x \\right )}\\, dx'

display(pi**2)
display(pi.evalf())
display((pi + exp(1)).evalf())

print('sqrt(2) を 100 桁まで評価')
display(sqrt(2).evalf(100))

print('無限大')
display(oo)
display(oo > 99999)
display(oo + 1)

無限大

display(expand(x + y, complex=True))
display(I*im(x) + I*im(y) + re(x) + re(y))
display(expand(cos(x + y), trig=True))
display(cos(x)*cos(y) - sin(x)*sin(y))

expr = (x + y)**5
display(expr)
print('多項式を展開してくれる: (x + y)**5')
display(expand(expr))

a = (x + x**2)/(x*sin(y)**2 + x*cos(y)**2)
print('式を単純化: (x + x**2)/(x*sin(y)**2 + x*cos(y)**2)')
display(simplify(a))

print('多項式の割り算: div(x**2 - 4 + x, x-2)')
display(div(x**2 - 4 + x, x-2))
print('最大公約数: gcd(2*x**2 + 6*x, 12*x)')
display(gcd(2*x**2 + 6*x, 12*x))
print('最小公倍数: lcm(2*x**2 + 6*x, 12*x)')
display(lcm(2*x**2 + 6*x, 12*x))
print('因数分解: factor(x**4/2 + 5*x**3/12 - x**2/3)')
display(factor(x**4/2 + 5*x**3/12 - x**2/3))
print('多変数の因数分解: factor(x**2 + 4*x*y + 4*y**2)')
display(factor(x**2 + 4*x*y + 4*y**2))
print('根を求める: solve(x**2 + 4*x*y + 4*y**2)')
display(solve(x**2 + 4*x*y + 4*y**2))
print('根を求める: solve(x**2 + 4*x*y + 4*y**2, y)')
display(solve(x**2 + 4*x*y + 4*y**2, y))
print('複雑な根を求める: solve(x**2 + 4*x + 181, x)')
display(solve(x**2 + 4*x + 181, x))
print('無理数解: solve(x**3 + 4*x + 181, x)')
display(solve(x**3 + 4*x + 181, x))
print('多変数多項式を解く: solve_poly_system([y**2 - x**3 + 1, y*x], x, y)')
display(solve_poly_system([y**2 - x**3 + 1, y*x], x, y))

多項式を展開してくれる: (x + y)**5

式を単純化: (x + x**2)/(x*sin(y)**2 + x*cos(y)**2)

多項式の割り算: div(x**2 - 4 + x, x-2)

最大公約数: gcd(2*x**2 + 6*x, 12*x)

最小公倍数: lcm(2*x**2 + 6*x, 12*x)

因数分解: factor(x**4/2 + 5*x**3/12 - x**2/3)

多変数の因数分解: factor(x**2 + 4*x*y + 4*y**2)

根を求める: solve(x**2 + 4*x*y + 4*y**2)

根を求める: solve(x**2 + 4*x*y + 4*y**2, y)

複雑な根を求める: solve(x**2 + 4*x + 181, x)

無理数解: solve(x**3 + 4*x + 181, x)

多変数多項式を解く: solve_poly_system([y**2 - x**3 + 1, y*x], x, y)

f = x**2 + 3*x + 2
display(f)
f1 = f.subs([(x, 1)])
display(f1)

expr = cos(x) * ln(y) + 2/y
display(expr)
display(solve(expr, x))
display(solve(x**4 - 1, x))
display(solve([x + 5*y - 2, -3*x + 6*y - 15], [x, y]))

f = x**4 - 3*x**2 + 1
display(factor(f))
display(factor(f, modulus=5))

print('超越方程式も一部サポート')
display(solve(exp(x) + 1, x))

超越方程式も一部サポート

display(satisfiable(x & y))
display(satisfiable(x & ~x))

{y: True, x: True}

False

x, y, z = symbols('x y z')
eq1 = x * y * z + 234
eq2 = x + y + z - 20
eq3 = 5 * x - y + 2 * z - 85
display(eq1)
display(eq2)
display(eq3)
solve([eq1,eq2,eq3], [x,y,z])

from sympy import Matrix
display(Matrix([[1,0], [0,1]]))

print('Numpy と違ってシンボルを含む行列が書ける')
x = Symbol('x')
y = Symbol('y')
A = Matrix([[1,x], [y,1]])
display(A)
display(A**2)

Numpy と違ってシンボルを含む行列が書ける

display(limit(tan(x), x, pi/2))
display(limit(tan(x), x, pi/2, dir="-"))
display(limit(sin(x)/x, x, 0))
 # 無限大は oo で
display(limit(sin(x)/x, x, oo))

display(diff((sin(x) * x**2) / (1 + tan(cot(x)))))
display(diff(cot(x*y), y))
display(diff(y(x)**2 - 5* sin(x), x))
f = x**2 / y + 2 * x - ln(y)
display(diff(f,x))

print('第 3 引数で指定する')
display(diff(sin(2*x), x, 1))
display(diff(sin(2*x), x, 2))
display(diff(sin(2*x), x, 3))

第 3 引数で指定する

 # 未定義の関数を定義
f, g = symbols('f g', cls=Function)
display(f)
display(f(x))
display(f(x).diff(x, x) + f(x))

diffeq = f(x).diff(x) + f(x)
display(dsolve(diffeq, f(x)))

diffeq = f(x).diff(x, x) + f(x)
display(dsolve(diffeq, f(x)))

diffeq = f(x).diff(x, x, x) + f(x)
display(dsolve(diffeq, f(x)))

 # キーワード引数を使ってヒントを出すこともできる。
 # 方程式が可分離であることを知っていルナらキーワードとして hint='separable'
display(dsolve(sin(x)*cos(f(x)) + cos(x)*sin(f(x))*f(x).diff(x), f(x), hint='separable'))

display(dsolve(x * f(x).diff(x) + f(x) - f(x) ** 2))
display(dsolve(x * f(x).diff(x) + f(x) - f(x) ** 2, hint='Bernoulli'))

f

display(sin(x).series(x))
display(series(sin(x), x, pi/2))

print('積分')
print('integrate(6*x**5, x)')
display(integrate(6*x**5, x))

display(integrate(sin(x), x))
display(integrate(log(x), x))
display(integrate(2*x + sinh(x), x))

expr = cos(x) * ln(y) + 2/y
display(integrate(expr, x))
display(integrate(tan(x)))
display(integrate(2*x + y, y))
display(integrate(2*x + y, (x, 1, 3)))
display(integrate(2*x + y, (x, 1, 3), (y, 2, 4)))

print('特殊関数もいける')
display(integrate(exp(-x**2)*erf(x), x))

print('定積分')
display(integrate(x**3, (x, -1, 1)))
display(integrate(sin(x), (x, 0, pi/2)))
display(integrate(cos(x), (x, -pi/2, pi/2)))

print('広義積分')
display(integrate(exp(-x), (x, 0, oo)))
display(integrate(exp(-x**2), (x, -oo, oo)))
display(integrate(tan(x), (x, 0, pi/2)))

print('積分の厳密解')
display(integrate(1/(x**2 + 1), (x, 0, oo)))
display(integrate(exp(x) / (1 + exp(2 * x))))
display(integrate((2 * x+3)**7))

積分
integrate(6*x**5, x)

特殊関数もいける

定積分

広義積分

積分の厳密解

for i in range(32):
    padded = str('{0:02d}'.format(i))
    tmpdate = "2017-08-" + padded
    print(tmpdate)
    print(tmpdate)

... ... ... ... 2017-08-00
2017-08-00
2017-08-01
2017-08-01
2017-08-02
2017-08-02
2017-08-03
2017-08-03
2017-08-04
2017-08-04
2017-08-05
2017-08-05
2017-08-06
2017-08-06
2017-08-07
2017-08-07
2017-08-08
2017-08-08
2017-08-09
2017-08-09
2017-08-10
2017-08-10
2017-08-11
2017-08-11
2017-08-12
2017-08-12
2017-08-13
2017-08-13
2017-08-14
2017-08-14
2017-08-15
2017-08-15
2017-08-16
2017-08-16
2017-08-17
2017-08-17
2017-08-18
2017-08-18
2017-08-19
2017-08-19
2017-08-20
2017-08-20
2017-08-21
2017-08-21
2017-08-22
2017-08-22
2017-08-23
2017-08-23
2017-08-24
2017-08-24
2017-08-25
2017-08-25
2017-08-26
2017-08-26
2017-08-27
2017-08-27
2017-08-28
2017-08-28
2017-08-29
2017-08-29
2017-08-30
2017-08-30
2017-08-31
2017-08-31

import datetime

print(datetime.date.today()) # 2021-05-15
print(datetime.datetime.today()) # 2021-05-15 23:58:55.230456

import datetime

print(datetime.date(2017, 11, 12)) # 2021-05-15
print(datetime.datetime(2017, 11, 12, 9, 55, 28)) # 2021-05-15 09:55:28

import datetime

now = datetime.datetime(2021, 05, 15, 10, 0, 0)
print(now.year) # 2021
print(now.month) # 5
print(now.day) # 15
print(now.hour) # 10
print(now.minute) # 00
print(now.second) # 00

#### 曜日
`weekday()`を使う.
値は次の通り.

| 数値 | 意味   |
|------|--------|
|    0 | 月曜日 |
|    1 | 火曜日 |
|    2 | 水曜日 |
|    3 | 木曜日 |
|    4 | 金曜日 |
|    5 | 土曜日 |
|    6 | 日曜日 |

```python
import datetime

d = datetime.date(2021, 5, 15)
print(d.weekday()) # 5

d = d + datetime.timedelta(days=1)
print(d.weekday()) # 6

d = d + datetime.timedelta(days=1)
print(d.weekday()) # 0

import datetime

now = datetime.datetime(2021, 5, 15, 10, 0, 0)
print(now.date()) # 2021-05-15

import datetime

now = datetime.datetime(2021, 5, 15, 10, 0, 0)
print(now.time()) # 10:00:00

import datetime

d = datetime.datetime(2021, 5, 15, 10, 0, 0)
print(d + datetime.timedelta(weeks=1))   # 2021-05-22 10:00:00
print(d + datetime.timedelta(days=1))    # 2021-05-16 10:00:00
print(d + datetime.timedelta(hours=1))   # 2021-05-15 11:00:00
print(d + datetime.timedelta(minutes=1)) # 2021-05-15 10:01:00
print(d + datetime.timedelta(seconds=1)) # 2021-05-15 10:00:01

import datetime
from dateutil.relativedelta import relativedelta

d = datetime.datetime(2021, 5, 15, 10, 0, 0)
print(d + relativedelta(years=1))   # 2022-05-15 10:00:00
print(d + relativedelta(months=1))  # 2021-06-15 10:00:00
print(d + relativedelta(weeks=1))   # 2021-05-22 10:00:00
print(d + relativedelta(days=1))    # 2021-05-16 10:00:00
print(d + relativedelta(hours=1))   # 2021-05-15 11:00:00
print(d + relativedelta(minutes=1)) # 2021-05-15 10:01:00
print(d + relativedelta(seconds=1)) # 2021-05-15 10:00:01

import datetime

d1 = datetime.datetime(2021, 5, 15, 10, 0, 0)
d2 = datetime.datetime(2021, 5, 15, 10, 0, 1)
print((d1 > d2))  # False
print((d1 >= d2)) # False
print((d1 < d2))  # True
print((d1 <= d2)) # True
print((d1 == d2)) # False

import datetime

d_str = "2021/5/15"
d = datetime.datetime.strptime(d_str, "%Y/%m/%d")
print(d) # 2021-05-15 00:00:00

dt_str = "2021/5/15 10:00:00"
dt = datetime.datetime.strptime(dt_str, "%Y/%m/%d %H:%M:%S")
print(dt) # 2021-05-15 10:00:00

import datetime

df = datetime.datetime(2021, 5, 15, 10, 0, 0)
print(df.strftime("%Y/%m/%d")) # 2021/05/15
print(df.strftime("%Y/%m/%d %H:%M:%S")) # 2021/05/15 10:00:00

import yaml

input_yaml_file_name = ymlname
output_yaml_file_name = "mkdocs.yml"
orig_data = {}
with open (input_yaml_file_name, "r", encoding="utf-8", newline="") as f:
    orig_data = yaml.load(f, Loader=yaml.FullLoader)
    del orig_data["plugins"][0]["search"]["prebuild_"]

try:
    pass # some process
except Exception as e:
    print(e)
    pass # some process

from pathlib import Path
p = Path(fname).as_posix()

from pathlib import Path
a = Path("/path/to").glob("**/*.org")

pip install pyyaml

import yaml

input_yaml_file_name = ymlname
output_yaml_file_name = "mkdocs.yml"
orig_data = {}
with open (input_yaml_file_name, "r", encoding="utf-8", newline="") as f:
    orig_data = yaml.load(f, Loader=yaml.FullLoader)
    del orig_data["plugins"][0]["search"]["prebuild_"]
with open(output_yaml_file_name, "w", encoding="utf-8", newline="") as f:
    yaml.dump(orig_data, f, encoding='utf-8', allow_unicode=True, default_flow_style=False)

import pathlib
path = "path/to/1.txt"
pathlib.Path(path).touch()

import os
os.makedirs(path, exist_ok=True)

def get_hnum(p):
    """ディレクトリの階層番号を取る"""
    if os.path.isdir(p):
        # ディレクトリならカウントする
        pstr = str(p.as_posix())
        h_num = len(pstr.split("/"))
    else:
        # ファイルは 1 にする
        h_num = 1
    return h_num - 1

import os
os.path.isdir(fname)

import shutil
shutil.move(from, to)

import os
os.path.isfile(fname)

import shutil
shutil.copyfile(from, to)

import os
fname = "some file name"
os.remove(fname)

import os
filepath = 'dir/subdir/filename.ext'
dirname, basename = os.path.split(filepath)

from pathlib import Path
Path('path/to').name

#読むとき
with open(fname, "r", encoding="utf-8", newline="") as f:
    pass # 何かの処理

#書くとき
with open(fname, "w", encoding="utf-8", newline="") as f:
    pass # 何かの処理

pip install jupytext
jupytext --to notebook --execute sample.py
jupytext --to notebook --execute arithmetic001.py

jupyter nbconvert --to script 00-introduction_01_install.ipynb --no-prompt

jupyter nbconvert --to script 00-introduction_01_install.ipynb --no-prompt

import logging
logger = logging.getLogger()
logger.setLevel(logging.CRITICAL)

import sys
sys.executable

jupyter kernelspec list

jupyter kernelspec list

jupyter kernelspec remove kernel_name

jupyter --version

letters = [chr(i) for i in range(97, 123)] # 小文字だけ
capitals = [chr(i) for i in range(65, 91)] # 大文字だけ

import string
all = [i for i in string.ascii_letters] # a-Z

>>> sorted("This is a test string from Andrew".split(), key=str.lower)
['a', 'Andrew', 'from', 'is', 'string', 'test', 'This']

a = [1, 2, 3, 4, 5]
print(a[::-1])
print(list(reversed(a)))

a.reverse()
print(a)

[1, 2, 3].join(",")

%matplotlib inline
import numpy as np
import matplotlib.pyplot as plt

n = 8
X, Y = np.mgrid[0:n, 0:n]
T = np.arctan2(Y - n / 2., X - n/2.)
R = 10 + np.sqrt((Y - n / 2.0) ** 2 + (X - n / 2.0) ** 2)
U, V = R * np.cos(T), R * np.sin(T)

plt.axes([0.025, 0.025, 0.95, 0.95])
plt.quiver(X, Y, U, V, R, alpha=.5)
plt.quiver(X, Y, U, V, edgecolor='k', facecolor='None', linewidth=.5)

plt.xlim(-1, n)
plt.xticks(())
plt.ylim(-1, n)
plt.yticks(())

plt.show()

import matplotlib.pyplot as plt
import numpy as np
from numpy import ma

X, Y = np.meshgrid(np.arange(0, 2 * np.pi, .2), np.arange(0, 2 * np.pi, .2))
U = np.cos(X)
V = np.sin(Y)


plt.figure()
Q = plt.quiver(U, V)
qk = plt.quiverkey(Q, 0.5, 0.92, 2, r'$2 \frac{m}{s}$', labelpos='W',
                   fontproperties={'weight': 'bold'})
l, r, b, t = plt.axis()
dx, dy = r - l, t - b
plt.axis([l - 0.05*dx, r + 0.05*dx, b - 0.05*dy, t + 0.05*dy])

plt.title('picture 1')

plt.figure()
Q = plt.quiver(X, Y, U, V, units='width')
qk = plt.quiverkey(Q, 0.9, 0.95, 2, r'$2 \frac{m}{s}$',
                   labelpos='E',
                   coordinates='figure',
                   fontproperties={'weight': 'bold'})
plt.axis([-1, 7, -1, 7])
plt.title('picture 2')

plt.figure()
Q = plt.quiver(X[::3, ::3], Y[::3, ::3], U[::3, ::3], V[::3, ::3],
               pivot='mid', color='r', units='inches')
qk = plt.quiverkey(Q, 0.5, 0.03, 1, r'$1 \frac{m}{s}$',
                   fontproperties={'weight': 'bold'})
plt.plot(X[::3, ::3], Y[::3, ::3], 'k.')
plt.axis([-1, 7, -1, 7])
plt.title("picture 3")

plt.figure()
M = np.hypot(U, V)
Q = plt.quiver(X, Y, U, V, M,
               units='x',
               pivot='tip',
               width=0.022,
               scale=1 / 0.15)
qk = plt.quiverkey(Q, 0.9, 1.05, 1, r'$1 \frac{m}{s}$',
                   labelpos='E',
                   fontproperties={'weight': 'bold'})
plt.plot(X, Y, 'k.')
plt.axis([-1, 7, -1, 7])
plt.title("picture 4")

plt.figure()
Q = plt.quiver(X[::3, ::3], Y[::3, ::3], U[::3, ::3], V[::3, ::3],
               color='r', units='x',
               linewidths=(2,), edgecolors=('k'), headaxislength=5)
qk = plt.quiverkey(Q, 0.5, 0.03, 1, r'$1 \frac{m}{s}$',
                   fontproperties={'weight': 'bold'})
plt.axis([-1, 7, -1, 7])
plt.title("picture 5")

plt.figure()
M = np.zeros(U.shape, dtype='bool')
M[U.shape[0]//3:2*U.shape[0]//3,
  U.shape[1]//3:2*U.shape[1]//3] = True
U = ma.masked_array(U, mask=M)
V = ma.masked_array(V, mask=M)
Q = plt.quiver(U, V)
qk = plt.quiverkey(Q, 0.5, 0.92, 2, r'$2 \frac{m}{s}$', labelpos='W',
                   fontproperties={'weight': 'bold'})
l, r, b, t = plt.axis()
dx, dy = r - l, t - b
plt.axis([l - 0.05 * dx, r + 0.05 * dx, b - 0.05 * dy, t + 0.05 * dy])
plt.title('picture 6')

plt.show()

%matplotlib inline
import matplotlib.pyplot as plt

x_numbers = [2, 4, 6]
y_numbers = [3, 4, 1]

plt.plot(x_numbers, y_numbers)
plt.savefig("tmp/graph_example001_tmp.png")
plt.show()

%matplotlib inline
import matplotlib.pyplot as plt

x_numbers = [2, 4, 5, 6]
y_numbers = [3, 4, 2, 1]

plt.plot(x_numbers, y_numbers, marker='o') # marker は 'o', '*', 'x', +' から選べる
plt.show()

%matplotlib inline
import matplotlib.pyplot as plt

x_numbers = [2, 4, 5, 6]
y_numbers = [3, 4, 2, 1]

plt.plot(x_numbers, y_numbers, 'o') # marker は 'o', '*', 'x', +' から選べる
plt.show()

%matplotlib inline
import matplotlib.pyplot as plt

x_numbers = [1, 2, 3]
y_numbers = [2, 4, 6]

plt.plot(x_numbers, y_numbers) # marker は 'o', '*', 'x', +' から選べる
plt.show()

%matplotlib inline
import matplotlib.pyplot as plt

lst = [53.9, 56.3, 56.4, 53.4, 54.5, 55.8, 56.8, 55.0, 55.3, 54.0, 56.7, 56.4, 57.3]
plt.plot(lst, marker='o')

%matplotlib inline
import matplotlib.pyplot as plt

num = 18
h_axis = range(num, num + len(lst))
plt.plot(h_axis, lst, marker='o')

%matplotlib inline
import matplotlib.pyplot as plt

h_axis_multiple = range(1, 13)
lst1 = [31.3, 37.3, 47.2, 51.0, 63.5, 71.3, 72.3, 72.7, 66.0, 57.0, 45.3, 31.1]
lst2 = [40.9, 35.7, 43.1, 55.7, 63.1, 71.0, 77.9, 75.8, 66.6, 56.2, 51.9, 43.6]
lst3 = [37.3, 40.9, 50.9, 54.8, 65.1, 71.0, 78.8, 76.7, 68.8, 58.0, 43.9, 41.5]

plt.plot(h_axis_multiple, lst1, h_axis_multiple, lst2, h_axis_multiple, lst3, marker='o')


plt.legend(['graph1', 'graph2', 'graph3'])

%matplotlib inline
import matplotlib.pyplot as plt

plt.plot(h_axis_multiple, lst1, h_axis_multiple, lst2, h_axis_multiple, lst3)

plt.title('graph title')
plt.xlabel('x axis')
plt.ylabel('y axis')
plt.legend(['graph1', 'graph2', 'graph3'])

%matplotlib inline
import matplotlib.pyplot as plt

lst = [53.9, 56.3, 56.4, 53.4, 54.5, 55.8, 56.8, 55.0, 55.3, 54.0, 56.7, 56.4, 57.3]
plt.plot(lst, marker='o')
plt.axis(xmin=-1)
plt.axis(xmax=13)
plt.axis(ymin=50)
plt.axis(ymax=60)

%matplotlib inline
import matplotlib.pyplot as plt


time_of_day = ['4 AM', '7 AM', '10 AM', '1 PM', '4 PM', '7PM', '10 PM']
forecast_temp = [10, 6, 15, 17, 20, 19, 16]
time_interval = range(1, len(time_of_day) + 1)

plt.plot(time_interval, forecast_temp, 'o-')

plt.xticks(time_interval, time_of_day)
plt.show()

%matplotlib inline
import numpy as np
import matplotlib.pyplot as plt

def draw_quadrant():
    """四分円の円周を描画"""
    circle_x = np.arange(0,1,0.001)
    circle_y = np.sqrt(1- circle_x * circle_x)
    plt.plot(circle_x, circle_y)
    plt.gca().set_aspect('equal', adjustable='box')
    plt.show()

draw_quadrant()

%matplotlib inline
import matplotlib.pyplot as plt
x_numbers = [1, 2, 3]
y_numbers = [2, 4, 6]
plt.plot(x_numbers, y_numbers)




plt.savefig('tmp/graph_example012_tmp.png')
plt.savefig('tmp/graph_example012_tmp.svg')
plt.savefig('tmp/graph_example012_tmp.pdf')

%matplotlib inline
import matplotlib.pyplot as plt

def create_circle():
    circle = plt.Circle((0, 0), radius = 0.5)
    return circle

def show_shape(patch):
    ax = plt.gca()
    ax.add_patch(patch)
    plt.axis('scaled')
    plt.show()

c = create_circle()
show_shape(c)

%matplotlib inline
import matplotlib.pyplot as plt


r = range(100, 1001, 20)

G = 6.674*(10**-11)

m1 = 0.5
m2 = 1.5

F = [G * (m1 * m2) / (dist ** 2) for dist in r]

plt.plot(r, F, marker='o')

plt.xlabel('Distance')
plt.ylabel('Newton gravitational force')
plt.title('A graph for the inverse square law')
plt.show()

%matplotlib inline
import matplotlib
import numpy as np
import matplotlib.pyplot as plt

matplotlib.rcParams['xtick.direction'] = 'out'
matplotlib.rcParams['ytick.direction'] = 'out'


a = 3.592
b = 0.0427
R = 0.08206


pointsnum = 1000



v = np.linspace(0.064, 0.18, pointsnum)
p = np.linspace(0, 100.0, pointsnum)
X, Y = np.meshgrid(v, p)


Z = (Y + (a / X ** 2)) * (X - b) / R


plt.figure()
CS = plt.contour(X, Y, Z, 25, linewidth=1.0, colors='k')
zc = CS.collections[0:8]
plt.setp(zc, linewidth=0.2, linestyle='dashed')

plt.clabel(CS, inline=1, fontsize=10, fmt='%4.0f')
plt.title('T (Kelvin)')
plt.xlabel('V (litres)')
plt.ylabel('P (atm)')
plt.show()

%matplotlib inline
import matplotlib.pyplot as plt
import math

def frange(start, final, interval):
    numbers = []
    # float だと range が使えないのでこの処理
    while start < final:
        numbers.append(start)
        start = start + interval

    return numbers

def get_trajectory(v0, theta):
    # 重力定数の定義
    g = 9.8

    # 入力の角度をラジアンに変換
    theta = math.radians(theta)

    # 着地までの時間の計算
    t_flight = 2 * v0 * math.sin(theta) / g

    # 着地時間までの時間リスト: dt 刻み
    dt = 0.001
    intervals = frange(0, t_flight, dt)

    # x, y 座標の計算
    x = []
    y = []
    for t in intervals:
        x.append(v0*math.cos(theta)*t)
        y.append(v0*math.sin(theta)*t - 0.5*g*t*t)

    return (x,y)

v0 = 20    # m/s
theta = 30 # 度数法で入力
tragectory = get_trajectory(v0, theta)

plt.plot(tragectory[0], tragectory[1])
plt.xlabel('x')
plt.ylabel('y')
plt.title('Projectile motion of a ball')
plt.show()