Author Archives: ddnro

GNU Emacs Basics – Part 1 – About and Installation

About GNU Emacs

GNU Emacs is a commonly used text editor. It is not the prettiest text editor out there but in my opinion it is one of the most useful tool that you will ever learn. It is used by many people ranging from casual user to programmers.

This series of posts is not intended to cover everything GNU Emacs can do, that would be nearly impossible, but to help you get started, understand its capabilities and of course to get work done. Personally, I use GNU Emacs in conjunction with Common LISP programming language as a programming environment.

Here are some of the features of GNU Emacs:

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How to open, read, and write text files in Python

Let’s say that you need to open, read, and write text files in Python. First you can use the open() built-in function to open the file. Once the file is opened you can use the two built-in methods read() and write() to read from the file and to write to the file.

>>> opened_file = open('file.txt')
>>> the_file_content = opened_file.read()
>>> the_file_content
'Hi there! I am a .txt file!'

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How to copy files using shutil module in Python

The shutil module contains many functions but two of them can be used to copy files from one location to another. To demonstrate this I created two text files named file1.txt and file2.txt.

You can copy the content of the file1.txt to the file2.txt. This way, both files will have the same content but they will still have their original names.

>>> import shutil
>>> new_file_path = shutil.copy('file1.txt', 'file2.txt')

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How to create classes of iterators using itertools module in Python

The itertools module provides iterators that you can use in your projects. One of the commonly used method is accumulate.

>>> import itertools
>>> accumulator = itertools.accumulate(range(10))
>>> next(accumulator)
0
>>> next(accumulator)
1
>>> next(accumulator)
3
>>> next(accumulator)
6
>>> next(accumulator)
10
>>> next(accumulator)
15

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How to extract and filter the content of an iterator in Python

Let’s say that you have an iterator and you need to list all the containing elements within it. In order to do that you can use the enumerate() function which will take an iterable object and return a list of tuples (count + value).

>>> bikes = ['Honda', 'Yamaha', 'Suzuki']
>>> bike_enum = enumerate(bikes)
>>> next(bike_enum)
(0, 'Honda')
>>> next(bike_enum)
(1, 'Yamaha')
>>> next(bike_enum)
(2, 'Suzuki')

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How to get the current date and time in Python

Let’s say you need the current date and time from your system to place it in a Python application. For example to place the date and time as a timestamp in a blog application so the date and time when a blog article was posted will be visible on the screen.

For that, we need to import a module called datetime which contains a class with the same name datetime.

>>> import datetime
>>> current_datetime = datetime.datetime.now()
>>> print(current_datetime)
2017-12-11 08:18:18.685000

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