### Creating an rudimentary interactive application in python with Pyface and Qt

So, I wanted to learn the Qt windowing framework and I wanted to be able to write code in Python, which I am comfortable with, instead of using C++. Pyface is one such projects that let you create and communicate with GUI elements made with Qt from Python. Coincidentally, it's one of the open source projects that my employer created and maintains.

Here you can see an example code that creates a window with a text area, created using the QTextEdit class. Given that I would like to know what's written in the text area, I can use the toPlainText() method of a QTextEdit object. Further, I would like to have some buttons which do something I want them to when the user clicks on them. Buttons are QPushButton() objects and object.clicked.connect.() method call links the button to a function/method/action of our liking. The layout of the text area and the buttons are set using a QVBoxLayout object.

Three references which helped me are mentioned at the top of the file. A first version of the code is also mentioned at the top of the file. Note that you will need the pyface Python library installed to be able to run the code. And, syntax and code highlighting is provided by this awesome website, which I sadly only just came across.

A few more references, if you would like, are :

As always, comments and suggestions are always welcome and are highly appreciated. Thank you.

# http://doc.qt.io/qt-4.8/gettingstartedqt.html
# http://zetcode.com/gui/pyqt4/firstprograms/
# https://doc.qt.io/archives/qq/qq19-buttons.html

"""
from pyface.qt.QtGui import QApplication
from pyface.qt.QtGui import QTextEdit

import sys

def main():
app = QApplication(sys.argv)
textEdit = QTextEdit()
textEdit.show()

app.exec_()
return
"""
import time
import sys

from pyface.qt.QtGui import *
from pyface.qt.QtCore import QCoreApplication

class mainclass():

app = QApplication(sys.argv)
textEdit = QTextEdit()

progressBar = QProgressBar()

def on_ok(self):
print 'yay'

def on_quit(self):
messageBox = QMessageBox()
messageBox.setText("Do you really want to quit?")
messageBox.setStandardButtons(QMessageBox().Yes | QMessageBox().No)
messageBox.setDefaultButton(QMessageBox().No)
if messageBox.exec_() == QMessageBox().Yes:
qApp.quit()

def on_cancel(self):
print 'do you want to cancel?'

def on_print(self):
print self.textEdit.toPlainText()

def updateProgressBar(self):
for i in range(100):
self.progressBar.setValue(i)
time.sleep(1)

def main(self):
quitButton = QPushButton("Quit")
# quitButton.clicked.connect(QCoreApplication.instance().quit)
quitButton.clicked.connect(self.on_quit)

cancelButton = QPushButton("Cancel")
cancelButton.clicked.connect(self.on_cancel)
okButton = QPushButton("OK")
okButton.clicked.connect(self.on_ok)
printButton = QPushButton("Print")
printButton.clicked.connect(self.on_print)

updateProgressBarButton = QPushButton("Update Progress Bar")
updateProgressBarButton.clicked.connect(self.updateProgressBar)

box = QDialogButtonBox()

layout = QVBoxLayout()

window = QWidget()
window.setLayout(layout)

window.show()

return self.app.exec_()

if __name__ == "__main__":
test = mainclass()
test.main()


### Animation using GNUPlot

Animation using GNUPlotI've been trying to create an animation depicting a quasar spectrum moving across the 5 SDSS pass bands with respect to redshift. It is important to visualise what emission lines are moving in and out of bands to be able to understand the color-redshift plots and the changes in it.
I've tried doing this using the animate function in matplotlib, python but i wasn't able to make it work - meaning i worked on it for a couple of days and then i gave up, not having found solutions for my problems on the internet.
And then i came across this site, where the gunn-peterson trough and the lyman alpha forest have been depicted - in a beautiful manner. And this got me interested in using js and d3 to do the animations and make it dynamic - using sliders etc.
In the meanwhile, i thought i'd look up and see if there was a way to create animations in gnuplot and whoopdedoo, what do i find but nirvana!

In the image, you see 5 static curves and one dynam…

### on MOOCs.

For those of you who don't know, MOOC stands for Massively Open Online Course.

The internet is an awesome thing. It's making education free for all. Well, mostly free. But it's surprising at the width and depth of courses being offered online. And it looks like they are also having an impact on students, especially those from universities that are not top ranked. Students in all parts of the world can now get a first class education experience, thanks to courses offered by Stanford, MIT, Caltech, etc.

I'm talking about MOOCs because one of my new year resolutions is to take online courses, atleast 2 per semester (6 months). And I've chosen the following two courses on edX - Analyzing Big Data with Microsoft R Server and Data Science Essentials for now. I looked at courses on Coursera but I couldn't find any which was worthy and free. There are a lot more MOOC providers out there but let's start here. And I feel like the two courses are relevant to where I …

### On programmers.

I just watched this brilliant keynote today. It's a commentary on Programmers and the software development industry/ecosystem as a whole.

I am not going to give you a tl;dr version of the talk because it is a talk that I believe everyone should watch, that everyone should learn from. Instead, I am going to give my own parallel-ish views on programmers and programming.
As pointed out in the talk, there are mythical creatures in the software development industry who are revered as gods. Guido Van Rossum, the creator of Python, was given the title Benevolent Dictator For Life (BDFL). People flock around the creators of popular languages or libraries. They are god-like to most programmers and are treated like gods. By which, I mean to say, we assume they don't have flaws. That they are infallible. That they are perfect.
And alongside this belief in the infallibility of these Gods, we believe that they were born programmers. That programming is something that people are born wit…