Python 3.7.11 : My colab tutorials - part 020.

The tutorial I created is a test and use of the Selenium WebDriver python package for to automate web browser interaction from Python.

This tutorial can be found on my GitHub account.

Python Qt5 : Drag and drop examples - part 001.

This tutorial si about drag and drop with PyQt5 and Python 3.9.6.

The drag and drop feature is very intuitive for the user.

The widgets should respond to the drag and drop events in order to store the data dragged into them. 

• DragEnterEvent provides an event which is sent to the target widget as dragging action enters it.
• DragMoveEvent is used when the drag and drop action is in progress.
• DragLeaveEvent is generated as the drag and drop action leaves the widget.
• DropEvent, on the other hand, occurs when the drop is completed. The event’s proposed action can be accepted or rejected conditionally.

Let's see two example, first is a drag and drop for one button:

#!/usr/bin/python
import sys
from PyQt5.QtCore import Qt, QMimeData
from PyQt5.QtGui import QDrag
from PyQt5.QtWidgets import QPushButton, QWidget, QApplication

class Button(QPushButton):

    def __init__(self, title, parent):
        super().__init__(title, parent)

    def mouseMoveEvent(self, e):

        if e.buttons() != Qt.RightButton:
            return

        mimeData = QMimeData()

        drag = QDrag(self)
        drag.setMimeData(mimeData)
        drag.setHotSpot(e.pos() - self.rect().topLeft())
        dropAction = drag.exec_(Qt.MoveAction)

    def mousePressEvent(self, e):
        super().mousePressEvent(e)
        if e.button() == Qt.LeftButton:
            print('press')


class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):

        self.setAcceptDrops(True)

        self.button = Button('Button', self)
        self.button.move(100, 65)

        self.setWindowTitle('Drag and drop with mouse - right click to move Button!')
        self.setGeometry(300, 300, 550, 450)

    def dragEnterEvent(self, e):
        e.accept()

    def dropEvent(self, e):
        position = e.pos()
        self.button.move(position)

        e.setDropAction(Qt.MoveAction)
        e.accept()

def main():
    
    app = QApplication(sys.argv)
    ex = Example()
    ex.show()
    app.exec_()

if __name__ == '__main__':
    main()

... this source code is for a drag and drop for a image file:

import sys, os
from PyQt5.QtWidgets import QApplication, QWidget, QLabel, QVBoxLayout
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPixmap


class ImageLabel(QLabel):
    def __init__(self):
        super().__init__()

        self.setAlignment(Qt.AlignCenter)
        self.setText('\n\n Drop Image Here \n\n')
        self.setStyleSheet('''
            QLabel{
                border: 3px dashed #bbb
            }
        ''')

    def setPixmap(self, image):
        super().setPixmap(image)

class AppDemo(QWidget):
    def __init__(self):
        super().__init__()
        
        self.setWindowTitle('Drag and drop one image to this window!')
        self.setGeometry(300, 300, 550, 450)

        self.setAcceptDrops(True)

        mainLayout = QVBoxLayout()

        self.photoViewer = ImageLabel()
        mainLayout.addWidget(self.photoViewer)

        self.setLayout(mainLayout)

    def dragEnterEvent(self, event):
        if event.mimeData().hasImage:
            event.accept()
        else:
            event.ignore()

    def dragMoveEvent(self, event):
        if event.mimeData().hasImage:
            event.accept()
        else:
            event.ignore()

    def dropEvent(self, event):
        if event.mimeData().hasImage:
            event.setDropAction(Qt.CopyAction)
            file_path = event.mimeData().urls()[0].toLocalFile()
            self.set_image(file_path)

            event.accept()
        else:
            event.ignore()

    def set_image(self, file_path):
        self.photoViewer.setPixmap(QPixmap(file_path))

app = QApplication(sys.argv)
demo = AppDemo()
demo.show()
sys.exit(app.exec_())

Python 3.7.11 : My colab tutorials - part 019.

The tutorial I created is a test and use Probabilistic Graphical Models for the most basic problem the coin problem with the pgmpy python module.

This tutorial can be found on my GitHub account.

News : The new python version 3.10.0.

Almost six days ago, the new version of python was released, version 3.10.0, see this.

Its installation on windows operating systems is done in the same way as the old installations, with the same steps and the same settings.

After installation, I turned it on and tested some of the new features.

C:\Python310>python
Python 3.10.0 (tags/v3.10.0:b494f59, Oct  4 2021, 19:00:18) [MSC v.1929 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.

Python 3.10 comes with precise and constructive error messages like:

...
SyntaxError: '{' was never closed
...
>>> foo(a, b for b in range(5), c)
...
    foo(a, b for b in range(5), c)
           ^^^^^^^^^^^^^^^^^^^
SyntaxError: Generator expression must be parenthesized
...
>>> {a, b for (a, b) in zip("a", "b")}
...
    {a, b for (a, b) in zip("a", "b")}
     ^^^^
SyntaxError: did you forget parentheses around the comprehension target?
...
SyntaxError: expected ':'
...
SyntaxError: invalid syntax. Perhaps you forgot a comma?
...
SyntaxError: ':' expected after dictionary key
...
SyntaxError: expected 'except' or 'finally' block
...
SyntaxError: cannot assign to attribute here. Maybe you meant '==' instead of '='?
...
IndentationError: expected an indented block after 'if' statement in line ...
...
>>> import collections
>>> collections.namedtoplo
...
AttributeError: module 'collections' has no attribute 'namedtoplo'. Did you mean: 'namedtuple'?
...
>>> a = 0
>>> aa
...
NameError: name 'aa' is not defined. Did you mean: 'a'?

PEP 634: Structural Pattern Matching Structural 

... the pattern matching is a comprehensive addition to the Python language. 

They tell us: Pattern matching enables programs to extract information from complex data types, branch on the structure of data, and apply specific actions based on different forms of data.

PEP 604: New Type Union Operator as X|Y 

PEP 613: Explicit Type Aliases 

PEP 647: User-Defined Type Guards 

PEP 612: Parameter Specification Variables

You can see more on the official webpage.

Python Qt5 : The QSvgWidget for the SVG image format.

In this example tutorial, I will show you how can show an SVG image format with the PyQt5 and QSvgWidget.

I used Fedora 35 Beta with python pyqt5 package install with pip tool.

$ pip install pyqt5

The source code in the Python programming language is this:

The result image is this:

The Hitchhiker’s Guide to Python.

Greetings, Earthling! Welcome to The Hitchhiker’s Guide to Python.

This project comes with this license, is free, and help you to learn Python:

Creative Commons Legal Code

Attribution-NonCommercial-ShareAlike 3.0 Unported ...

This guide is currently under heavy development. This opinionated guide exists to provide both novice and expert Python developers a best practice handbook to the installation, configuration, and usage of Python on a daily basis.

You can contribute to this project on the GitHub project.

Python 3.7.11 : My colab tutorials - part 018.

In this colab tutorial, you can see how to use the webcam with python and javascript.

This colab notebook can be found on my colab project on the GitHub webpage.

• catafest_001.ipynb - first step, import TensorFlow;
• catafest_002.ipynb - testing the GPU , Linux commands and python modules torch and fastai;
• catafest_003.ipynb - testing the Altair;
• catafest_004.ipynb - testing the cirq python package for quantum computing;
• catafest_005.ipynb - using the estimator on tensoflow 2.0;
• python_imdb_001.ipynb - using the colab with python module imdbpy;
• catafest_006.ipynb - google authentification and google.colab drive and files
• catafest_007.ipynb - test with https://github.com/harrism/numba_examples/blob/master/mandelbrot_numba.ipynb
• catafest_008.ipynb - few simple examples with selenium and chromium-chromedriver;
• catafest_009.ipynb - show you how to use %% colab features;
• catafest_010.ipynb - example with Detectron2 is Facebook AI Research's with state-of-the-art object detection algorithms;
• catafest_011.ipynb - test a sound classification with YAMNet from a web example - not very happy with the result;
• catafest_012.ipynb - a simple tutorial about Colab tool and HTML and JavaScript with examples;
• catafest_013.ipynb - a simple tutorial with settings for TPU and IMDB dataset;
• catafest_014.ipynb - get IMDB review dataset and show it;
• catafest_015.ipynb - how to get, show and use it data and create a new train data set from IMDB dataset;
• catafest_016.ipynb - show the shape of the Fashion-MNIST dataset;
• catafest_017.ipynb - this example show you how to write another python script in colab and run it;
• catafest_018.ipynb - PIFuHD demo;
• catafest_019.ipynb - get title from tiles.virtualearth.net;
• catafest_020.ipynb - get video from youtube with pytube, converting to audio, show signal wave, energy and frequency;
• catafest_021.ipynb - BERT is a transformers model with example and sentiment-analysis;
• catafest_022.ipynb - webcam on colab with python and javascript;

Python 3.7.11 : My colab tutorials - part 017.

BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding, see this https://arxiv.org/abs/1810.04805.

I used transformers, see this video: https://www.youtube.com/watch?v=SZorAJ4I-sA and this: https://arxiv.org/pdf/2003.08271.pdf.

See this colab notebook with examples at my GitHub account.

Python 3.7.11 : My colab tutorials - part 016.

This new colab notebook comes with: get youtube videos with pytube, converting to audio, show signals, energy and frequency.

You can see this work on the GitHub account.

Python 3.7.11 : My colab tutorials - part 015.

Google Maps explicitly forbid using map tiles offline or caching them, but I think Microsoft Bing Maps don't say anything explicitly against it, and I guess you are not planning to use your program commercially (?)

This colab notebook show you how to get a title from tiles.virtualearth.net.

The source code is simple:

class TileServer(object):
    def __init__(self):
        self.imagedict = {}
        self.mydict = {}
        self.layers = 'ROADMAP'
        self.path = './'
        self.urlTemplate = 'http://ecn.t{4}.tiles.virtualearth.net/tiles/{3}{5}?g=0'
        self.layerdict = {'SATELLITE': 'a', 'HYBRID': 'h', 'ROADMAP': 'r'}

    def tiletoquadkey(self, xi, yi, z, layers):
        quadKey = ''
        for i in range(z, 0, -1):
            digit = 0
            mask = 1 << (i - 1)
            if(xi & mask) != 0:
                digit += 1
            if(yi & mask) != 0:
                digit += 2
            quadKey += str(digit)
        return quadKey

    def loadimage(self, fullname, tilekey):
        im = Image.open(fullname)
        self.imagedict[tilekey] = im
        return self.imagedict[tilekey]

    def tile_as_image(self, xi, yi, zoom):
        tilekey = (xi, yi, zoom)
        result = None
        try:
            result = self.imagedict[tilekey]
            print(result)
        except:
            print(self.layers)
            filename = '{}_{}_{}_{}.jpg'.format(zoom, xi, yi, self.layerdict[self.layers])
            print("filename is " + filename)
            fullname = self.path + filename
            try:
                result = self.loadimage(fullname, tilekey)
            except:
                server = random.choice(range(1,4))
                quadkey = self.tiletoquadkey(*tilekey)
                print (quadkey)
                url = self.urlTemplate.format(xi, yi, zoom, self.layerdict[self.layers], server, quadkey)
                print ("Downloading tile %s to local cache." % filename)
                urllib.request.urlretrieve(url, fullname)
                #urllib.urlretrieve(url, fullname)
                result = self.loadimage(fullname, tilekey)
        return result

Simple install of python in Windows O.S.

Today I create this simple video tutorial for new python users.

In this video tutorial I show you how easy is to install the python programming language in Windows O.S.

After install you can use the command python and you can use the python shell to test this programming language.

Also, you can create a script file with any name.

for example name the file: test.py and run in the windows shell with: python test.py.

You can see this video tutorial on my youtube account.

Python Qt6 : Install and use python with Visual Studio.

Visual Studio is a very good tool for python programming language development.

Today I will show you how to use it with Visual Studio on a Windows operating system.

If you don't have Python install then start the Visual Studio installer and from all presents select the Python development workload.

Start Visual Studio and open a folder or open an empty file and save with the python language-specific extension: py.

Select the Python environment and add the new package with pip tool.

This is the python script I used to test:

import sys
from PyQt6.QtWidgets import QApplication, QWidget

def main():

    app = QApplication(sys.argv)

    w = QWidget()
    w.resize(250, 200)
    w.move(300, 300)

    w.setWindowTitle('Simple')
    w.show()

    sys.exit(app.exec())

if __name__ == '__main__':
    main()

You can see the video tutorial about how you can use it:

Python Qt6 : First example on Fedora 34 Linux distro.

Qt for Python is the project that provides the official set of Python bindings (PySide6) that will supercharge your Python applications. While the Qt APIs are world renowned, there are more reasons why you should consider Qt for Python.

I tested with Fedora 34 Linux distro:

[root@desk mythcat]# dnf search PyQt6
Last metadata expiration check: 2:03:10 ago on Tue 06 Jul 2021 08:52:41 PM EEST.
No matches found. 

First stable release for PyQt6 was on Jan 2021 by Riverbank Computing Ltd. under GPL or commercial and can be used with Python 3.

Let's install with pip tool:

[mythcat@desk ~]$ /usr/bin/python3 -m pip install --upgrade pip
...
  WARNING: The scripts pip, pip3 and pip3.9 are installed in '/home/mythcat/.local/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, 
  use --no-warn-script-location.
Successfully installed pip-21.1.3
[mythcat@desk ~]$ pip install PyQt6 --user
...

Let's see a simple example with this python package:

import sys
from PyQt6.QtCore import Qt
from PyQt6.QtWidgets import QApplication, QLabel

def main():
    app = QApplication(sys.argv)
    win = QLabel()
    win.resize(640, 498)
    win.setText("Qt is awesome!!!")
    win.show()
    app.exec()

if __name__ == "__main__":
    main()

I tested and run well.