나를 위한 기록

Below is a simple example. v = numpy.linspace(0.0, 1.0, 100, endpoint=True) contourf(xx,yy,zz,v) colorbar() cs = contour(xx,yy,zz,v, colors='white') clabel(cs, inline=1, fontsize=10) show()

[ref. https://matplotlib.org/3.1.0/gallery/color/named_colors.html ]

Summary of decimal point control of float format in Python  >>> 125650429603636838/(2**53)   13.949999999999999   >>> 234042163/(2**24)   13.949999988079071   >>> a=13.946   >>> print(a)   13.946   >>> print("%.2f" % a)   13.95   >>> round(a,2)   13.949999999999999   >>> print("%.2f" % round(a,2))   13.95   >>> print("{0:.2f}".format(a))   13.95   >>> print("{0:.2f}".format(round(a,2)))   13.95   >>> print("{0:.15f}".format(round(a,2)))   13.949999999999999 Thanks, JF ref.  https://stackoverflow.com/questions/455612/limiting-floats-to-two-decimal-points .

Use del as below. df = pandas.read_csv['filename.txt'] del df Thanks, JF

Up arrow key does not work in Python IDLE Editor to pull out the previous command. Alt + p : Previous commend Alt + n : Next commend Let's try these! Thanks, JF

Here is a sample code. import pandas as pd import matplotlib.pyplot as plt filename = 'a.txt' data = pd.read_csv(filename, sep='\t', header=None) plt.plot(data[0],data[1]) plt.xlabel('Raman shift (cm-1)', size=14) plt.ylabel('Intensity', size=14) plt.xlim(1000,3000) plt.savefig('Raman.png', transparent=True) plt.show() This is the link on details of read_csv of pandas. ( https://pandas.pydata.org/pandas-docs/stable/generated/pandas.read_csv.html ) This is the link on details of matplotlib.pyplot. ( https://matplotlib.org/api/_as_gen/matplotlib.pyplot.html ) Thanks, JF

If you give a command as below: mpirun -np 12 python pythoncode.py , same 12 jobs (python pythoncode.py) will be executed. Thanks, JF

I am going to use only one function for all of these. I will generate random numbers between 0 and 1. import numpy as np number = numpy.random.uniform(0, 1) array = numpy.random.uniform(0,1,n) # n is array size matrix = numpy.random.uniform(0,1,(n,m)) # n x m matrix Thanks, JF

1. Download PythonO.O.tgz 2. Unzip >> tar -xvzf PythonO.O.tgz 3. cd PythonO.O 4. ./confiure --prefix=$HOME/python27/           (example) 5. make 6. make install 7. Setup environment variables Thanks, JF

If you want to execute Linux command in Python code, use os.system. For example, import os os.system('ls') Above commands will show you a file list in your directory. When it comes to exitcode, os.system('command') will give (return) you an exit value, and value 0 means success. Thanks, JF

minimum value -> min(list) index of minimum value in list -> list.index(min(list)) Thanks, JF

If you want to use argument in Python, do this! sys.argv[1] : first argument sys.argv[2] : second argument sys.argv[n] : nth argument For example, num = int(sys.argv[1]) : store first argument as an integer type Thanks, JF

Today I am going to post about installing python modules such as setuptools, pytz, and six using pip ! If the environment variable of 'C:\python27' are not set, go to the folder of C:\python27. If you are using powershell, it is like below PS C:\Python27> For example, install six module PS C:\Python27> .\python.exe -m pip install six If you want to upgrade this module PS C:\Python27> .\python.exe -m pip install --upgrade six Thanks !

Back slash (\) could be used for line break and line continuation in Python! a = 12 + 13 + 14 + 15 is same as a = 12 + 13 \       + 14 + 15 Thanks, Have fun!

Using math module, like this! ------------------------------ import math print math.log(arg) ------------------------------ Above command will return the natural logarithm of x ( to base e ). Here is an example with some application to the other important cases!

Using random module, you can generate random number from 0 to 1 in float format. import random rannum = random.random() Here is an example!

We can generate empty matrix without numpy module in Python! Just do this! mat = [[0 for i in range(5)] for i in range(5)] Here is an example!

It is quite simple! ------------------------------- import numpy numpy.zeros([rows,cols]) ------------------------------- Here is an example!

First, visit the website of 'scipy.org' And then go to Install! (Left-Top direction) In this post, we will use the Anaconda server! click Anaconda link in the middle of page! From this page, you can download the Scipy package by clicking the button Finally, just double click the .exe file and follow the instructions after downloading the installer! Thanks! Have Fun!

In usual case, we are plotting graphs about integer or float x or y values, but sometimes you need to plot some graphs using string x or y values such as dates, categories. In this case, you can easily draw plot with string values by using xticks or yticks module. In this post, I will show you an example using x string values. Just for integer plot ----------------------------------------------------------------------------- from pylab import * x = [ 1, 2, 3 ] y = [ 2, 5, 10 ] plot(x, y) show() ----------------------------------------------------------------------------- The results is like below Now, for string x values --------------------------------------------------------------------- from pylab import * x = [ 'Mon' , 'Tue' , 'Wed' ] y = [ 2, 5, 10 ] plot( range ( len (y)), y) xticks( range ( len (y)), x, size= 'small' ) show() --------------------------------------------------------------------