pythonでグラフを描画（matplotlib）
グラフの例（sin関数）
【Python入門】ライブラリmatplotlibの基本的な使い方 - Qiita
[~/git/work/src/python] $ cat test.py import math import numpy as np from matplotlib import pyplot pi = math.pi x = np.linspace(0, 2*pi, 100) y = np.sin(x) pyplot.plot(x, y) pyplot.show() [~/git/work/src/python] $
実行
python3 test.py
以下、これを表示するまでのエラー
エラー対応
参考
matplotlibが描画されない - DISTRICT 37
python - python3 で _tkinter を import したい - スタック・オーバーフロー
ImportError:
Importing the multiarray numpy extension module failed. Most
likely you are trying to import a failed build of numpy.
If you're working with a numpy git repo, try `git clean -xdf` (removes all
files not under version control). Otherwise reinstall numpy.
Original error was: /usr/local/lib/python2.7/dist-packages/numpy/core/multiarray.so: undefined symbo
l: _Py_ZeroStruct
[~/git/work/src/python/software-design/saikyu-kouka] $ pip3 install numpy
Traceback (most recent call last):
File "/usr/local/bin/pip3", line 7, in <module>
from pip import main
File "/usr/local/lib/python3.6/site-packages/pip/__init__.py", line 26, in <module>
from pip.utils import get_installed_distributions, get_prog
File "/usr/local/lib/python3.6/site-packages/pip/utils/__init__.py", line 16, in <module>
import subprocess
File "/usr/local/lib/python3.6/subprocess.py", line 136, in <module>
import _posixsubprocess
ImportError: /usr/local/lib/python2.7/dist-packages/_posixsubprocess.so: undefined symbol: Py_InitMo
dule4_64
や
Traceback (most recent call last):
File "test.py", line 3, in <module>
from matplotlib import pyplot
File "/usr/local/lib/python3.6/site-packages/matplotlib/pyplot.py", line 113, in <module>
_backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
File "/usr/local/lib/python3.6/site-packages/matplotlib/backends/__init__.py", line 60, in pylab_setup
[backend_name], 0)
File "/usr/local/lib/python3.6/site-packages/matplotlib/backends/backend_tkagg.py", line 6, in <module>
from six.moves import tkinter as Tk
File "/usr/local/lib/python2.7/dist-packages/six.py", line 92, in __get__
result = self._resolve()
File "/usr/local/lib/python2.7/dist-packages/six.py", line 115, in _resolve
return _import_module(self.mod)
File "/usr/local/lib/python2.7/dist-packages/six.py", line 82, in _import_module
__import__(name)
File "/usr/local/lib/python3.6/tkinter/__init__.py", line 36, in <module>
import _tkinter # If this fails your Python may not be configured for Tk
ModuleNotFoundError: No module named '_tkinter'
などのエラーが出た
もう面倒になったので、pyenvをつくって、入れ直した
$ sudo apt install python3-pip python3-dev $ pyenv install 3.5.4 $ pyenv local 3.5.4 $ pyenv versions system * 3.5.4 (set by /home/ludwig125/git/work/src/python/.python-version) $
python3のパスを確認
$ which python3 /home/ludwig125/.pyenv/shims/python3 $ /home/ludwig125/.pyenv/shims/python3 --version Python 3.5.4 $
追加で必要なライブラリをインストール
$ python3 -m pip install numpy $ python3 -m pip install matplotlib
tkinterが使えることを確認
$ python3 -m tkinter
グラフの例（１次関数）
$ cat y-is-10x.py import matplotlib.pyplot as plt import numpy as np x = np.linspace(0, 99, 100) y = x * 10 plt.plot(x, y) plt.show()
実行結果
$ python3 y-is-10x.py
グラフの例（ノイズの入った１次関数）
$ cat noisy_y.py import matplotlib.pyplot as plt import numpy as np x = np.linspace(0, 99, 100) f_noisy = np.vectorize(lambda x: x * 10 + np.random.normal(0, 100)) d = f_noisy(x) plt.plot(x, d) plt.show()
実行結果
python3 noisy_y.py
グラフの例（放物線）
$ cat throw.py from math import sin, cos, radians from matplotlib import pyplot as plt def throw(x, y, v0, angle, repeatNum, dt): isSuccess = False xarray = []; yarray = [] vx = v0*cos( radians(angle) ) vy = v0*sin( radians(angle) ) ax = 0.0 ay = -9.8 for i in range(repeatNum): x = x + (vx + ax*dt/2)*dt y = y + (vy + ay*dt/2)*dt vx = vx + ax * dt vy = vy + ay * dt xarray.append(x) yarray.append(y) return (xarray, yarray, isSuccess) def prepareFigureArea(): plt.figure(figsize=(5, 5)) plt.xlim([0, 5]) plt.ylim([0, 5]) plt.xlabel('X - Axis (m)') plt.ylabel('Y - Axis (m)') return x1, y1, isSuccess = throw(0, 0, 6, 35, 500, 0.01) x2, y2, isSuccess2 = throw(0, 0, 6, 45, 500, 0.01) x3, y3, isSuccess3 = throw(0, 0, 6, 55, 500, 0.01) x4, y4, isSuccess3 = throw(0, 0, 6, 70, 500, 0.01) prepareFigureArea() plt.plot(x1, y1, 'bo-', x2, y2, 'ro-', x3, y3, 'ko-', x4, y4, 'yo-') plt.legend(['35 deg.', '45 deg.', '55 deg.', '70 deg.']) plt.show()
実行結果
python3 throw.py
以下が必要だったのでpip3 install
$ pip3 install six $ pip3 install pyparsing $ pip3 install cycler $ pip3 install python-dateutil --upgrade
