Узнайте о последовательном чтении в Python — PySerial

Последовательные порты — это интерфейсы последовательной связи, через которые информация передается последовательно, по одному биту за раз. С другой стороны, параллельные порты передают несколько битов одновременно. PySerial и такие функции, как последовательное чтение Python, упрощают связь с последовательными портами.

О пакете PySerial

Python на компьютере с установленным пакетом PySerial может взаимодействовать с внешним оборудованием. Это полезный пакет для решения проблем, поскольку он облегчает обмен данными между компьютерами и внешним оборудованием, таким как вольтметры, расходомеры, фонари и другие устройства, которые отправляют информацию через порты.

Установка модуля

Пакет PySerial НЕ является частью стандартной библиотеки Python. Поэтому устанавливайте вручную. Пакет Anaconda Distribution of Python поставляется с предустановленным пакетом.

Команда установки PIP

$ pip install pyserial

Команда подсказки Анаконды

> conda install pyserial

Импорт модуля + проверка установки

После установки версию можно проверить с помощью следующей команды.

import serial
print(serial.version)

О функции

serial.read()

Аргументы — передайте целочисленное значение, чтобы указать количество возвращаемых байтов.

Возвращает — предоставляет нам количество указанных байтов.

Использование функции последовательного чтения Python для получения информации из последовательных портов

Последовательное чтение Python — важная функция модуля. Это позволяет нам разгребать информацию, которая предоставляется из портов. Вот реализация Python, которая поможет нам в этом.

with serial.Serial('/my/sample1', 3443, timeout=1) as serial:
     readOneByte = serial.read()          
     readTenByte = serial.read(10)        

Объяснение

By default, .read() reads one byte at a time. By providing an integer value, you can set how many bytes of information are to be read by the function. 

Последовательное чтение Python против Readline

serial.read()	serial.readline()
serial.read()будет возвращать по одному байту за раз.	serial.readline()вернет все байты, пока не достигнет EOL.
Если внутри функции указано целое число, оно вернет столько байтов. Пример: serial.read(20) вернет 20 байт.	Вместо использования serial.read()более итераций serial.readline()можно использовать.

Использование последовательного чтения + записи на Raspberry Pi

Убедитесь, что ваш Raspberry Pi обновлен, выполнив следующие команды.

sudo apt update
sudo apt upgrade

Чтение данных

ser = serial.Serial(
        # Serial Port to read the data from
        port='/dev/ttyUSB0',
 
        #Rate at which the information is shared to the communication channel
        baudrate = 9600,
   
        #Applying Parity Checking (none in this case)
        parity=serial.PARITY_NONE,
 
       # Pattern of Bits to be read
        stopbits=serial.STOPBITS_ONE,
     
        # Total number of bits to be read
        bytesize=serial.EIGHTBITS,
 
        # Number of serial commands to accept before timing out
        timeout=1
)
# Pause the program for 1 second to avoid overworking the serial port
while 1:
        x=ser.readline()
        print x

Запись данных

import time
import serial
 
ser = serial.Serial(
        # Serial Port to read the data from
        port='/dev/ttyUSB0',
 
        #Rate at which the information is shared to the communication channel
        baudrate = 9600,
   
        #Applying Parity Checking (none in this case)
        parity=serial.PARITY_NONE,
 
       # Pattern of Bits to be read
        stopbits=serial.STOPBITS_ONE,
     
        # Total number of bits to be read
        bytesize=serial.EIGHTBITS,
 
        # Number of serial commands to accept before timing out
        timeout=1
)
counter=0
 
  
# Mentions the Current Counter number for each line written
# Pauses for one second each iteration to avoid overworking the port
while 1:
        ser.write("Write counter: %d \n"%(counter))
        time.sleep(1)
        counter += 1

Последовательное чтение Python в шестнадцатеричном формате

С помощью .hex() функции мы сохраняем байтовые данные в шестнадцатеричном формате в переменнойhexData

import serial
 
ser = serial.Serial(
    port='/samplePort/ttyUSB1',
    baudrate=115200,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,
    bytesize=serial.EIGHTBITS,
    timeout = None
)
 
while 1:
    print ser.read()
    hexData= ser.read().hex()
    print hexData

Функция Python pySerial in_waiting

Эту функцию можно использовать для получения количества байтов во входном буфере .

Возврат (ы) - целое число

Аргументы - нет

Аналогично работает функция out_waiting(). Он предоставляет количество байтов в выходном буфере.

Вот пример программы, реализующей указанную функцию.

import serial
ser = serial.Serial(
    port = '/samplePort/myUSB',
    baudrate = 5000,
    parity = serial.PARITY_NONE,
    stopbits = serial.STOPBITS_ONE,
    bytesize = serial.EIGHTBITS,
    timeout=0.5, 
    inter_byte_timeout=0.1
    )
 
# Reads one byte of information
myBytes = ser.read(1) 
 
# Checks for more bytes in the input buffer
bufferBytes = ser.inWaiting()
 
# If exists, it is added to the myBytes variable with previously read information
if bufferBytes:
    myBytes = myBytes + ser.read(bufferBytes)
    print(myBytes)

Функция Python pySerial flush()

flush()удаляет содержимое внутреннего буфера файлового объекта. Он не принимает никаких аргументов и ничего не возвращает. Существует 2 типа функций смыва:

• flushInput()- Очищает входной буфер
• flushOutput()- Очищает буфер вывода

import serial
ser = serial.Serial('/samplePort/myUSB10')
# Clearing Input Buffer
ser.flushInput()
 
# Clearing Output Buffer
ser.flushOutput()
ser.write("get") 
 
# Pause for 100 milliseconds
sleep(.1)
print ser.read()

Чтение данных с плат Arduino с помощью Python Serial Read

Arduino — это электронная платформа с открытым исходным кодом, которая предоставляет простое в использовании аппаратное и программное обеспечение. Платы Arduino могут считывать входные данные с датчиков, нажатия пальцем на кнопку или сообщения в Твиттере, которые затем выводятся в виде моторов, светодиодов или даже текста.

import serial
import time
 
ser = serial.Serial('COM4', 9800, timeout=1)
time.sleep(2)
 
for i in range(50):
    # Reading all bytes available bytes till EOL
    line = ser.readline() 
    if line:
        # Converting Byte Strings into unicode strings
        string = line.decode()  
        # Converting Unicode String into integer
        num = int(string) 
        print(num)
 
ser.close()

Распространенные ошибки

Питон AttribотсутствуетError: 'module' object has no attribute 'Serial'

Для решения этой проблемы попробуйте переименовать файл проекта в «serial.py». Удалите serial.pyc, если он существует. После этого бег import serial.

Кроме того, эта проблема возникает из-за того, что имя импортируемого вами пакета совпадает с именем файла вашего проекта.

Часто задаваемые вопросы о последовательном чтении Python

Можем ли мы читать несколько байтов за раз при последовательном чтении?

Функция .read()получает только один байт за раз. Однако мы можем итерировать функцию для получения одного байта за раз в нескольких циклах. Это довольно избыточно. Будет .readline()считан полный набор байтов, пока не будет достигнут EOL.

Вывод

Мы узнали, что с помощью модуля PySerial и Python Serial Read мы можем обрабатывать информацию с устройств через последовательные порты.

Источник:  https://www.pythonpool.com

#python 

What is GEEK

Buddha Community

Why use Python for Software Development

No programming language is pretty much as diverse as Python. It enables building cutting edge applications effortlessly. Developers are as yet investigating the full capability of end-to-end Python development services in various areas. 

By areas, we mean FinTech, HealthTech, InsureTech, Cybersecurity, and that's just the beginning. These are New Economy areas, and Python has the ability to serve every one of them. The vast majority of them require massive computational abilities. Python's code is dynamic and powerful - equipped for taking care of the heavy traffic and substantial algorithmic capacities. 

Programming advancement is multidimensional today. Endeavor programming requires an intelligent application with AI and ML capacities. Shopper based applications require information examination to convey a superior client experience. Netflix, Trello, and Amazon are genuine instances of such applications. Python assists with building them effortlessly. 

5 Reasons to Utilize Python for Programming Web Apps 

Python can do such numerous things that developers can't discover enough reasons to admire it. Python application development isn't restricted to web and enterprise applications. It is exceptionally adaptable and superb for a wide range of uses.

Robust frameworks 

Python is known for its tools and frameworks. There's a structure for everything. Django is helpful for building web applications, venture applications, logical applications, and mathematical processing. Flask is another web improvement framework with no conditions. 

Web2Py, CherryPy, and Falcon offer incredible capabilities to customize Python development services. A large portion of them are open-source frameworks that allow quick turn of events. 

Simple to read and compose 

Python has an improved sentence structure - one that is like the English language. New engineers for Python can undoubtedly understand where they stand in the development process. The simplicity of composing allows quick application building. 

The motivation behind building Python, as said by its maker Guido Van Rossum, was to empower even beginner engineers to comprehend the programming language. The simple coding likewise permits developers to roll out speedy improvements without getting confused by pointless subtleties. 

Utilized by the best 

Alright - Python isn't simply one more programming language. It should have something, which is the reason the business giants use it. Furthermore, that too for different purposes. Developers at Google use Python to assemble framework organization systems, parallel information pusher, code audit, testing and QA, and substantially more. Netflix utilizes Python web development services for its recommendation algorithm and media player. 

Massive community support 

Python has a steadily developing community that offers enormous help. From amateurs to specialists, there's everybody. There are a lot of instructional exercises, documentation, and guides accessible for Python web development solutions. 

Today, numerous universities start with Python, adding to the quantity of individuals in the community. Frequently, Python designers team up on various tasks and help each other with algorithmic, utilitarian, and application critical thinking. 

Progressive applications 

Python is the greatest supporter of data science, Machine Learning, and Artificial Intelligence at any enterprise software development company. Its utilization cases in cutting edge applications are the most compelling motivation for its prosperity. Python is the second most well known tool after R for data analytics.

The simplicity of getting sorted out, overseeing, and visualizing information through unique libraries makes it ideal for data based applications. TensorFlow for neural networks and OpenCV for computer vision are two of Python's most well known use cases for Machine learning applications.

Summary

Thinking about the advances in programming and innovation, Python is a YES for an assorted scope of utilizations. Game development, web application development services, GUI advancement, ML and AI improvement, Enterprise and customer applications - every one of them uses Python to its full potential. 

The disadvantages of Python web improvement arrangements are regularly disregarded by developers and organizations because of the advantages it gives. They focus on quality over speed and performance over blunders. That is the reason it's a good idea to utilize Python for building the applications of the future.

#python development services #python development company #python app development #python development #python in web development #python software development

Python Tricks Every Developer Should Know

Python is awesome, it’s one of the easiest languages with simple and intuitive syntax but wait, have you ever thought that there might ways to write your python code simpler?

In this tutorial, you’re going to learn a variety of Python tricks that you can use to write your Python code in a more readable and efficient way like a pro.

Let’s get started

Swapping value in Python

Instead of creating a temporary variable to hold the value of the one while swapping, you can do this instead

>>> FirstName = "kalebu"
>>> LastName = "Jordan"
>>> FirstName, LastName = LastName, FirstName 
>>> print(FirstName, LastName)
('Jordan', 'kalebu')

#python #python-programming #python3 #python-tutorials #learn-python #python-tips #python-skills #python-development

How to Remove all Duplicate Files on your Drive via Python

Today you’re going to learn how to use Python programming in a way that can ultimately save a lot of space on your drive by removing all the duplicates.

Intro

In many situations you may find yourself having duplicates files on your disk and but when it comes to tracking and checking them manually it can tedious.

Heres a solution

Instead of tracking throughout your disk to see if there is a duplicate, you can automate the process using coding, by writing a program to recursively track through the disk and remove all the found duplicates and that’s what this article is about.

But How do we do it?

If we were to read the whole file and then compare it to the rest of the files recursively through the given directory it will take a very long time, then how do we do it?

The answer is hashing, with hashing can generate a given string of letters and numbers which act as the identity of a given file and if we find any other file with the same identity we gonna delete it.

There’s a variety of hashing algorithms out there such as

• md5
• sha1
• sha224, sha256, sha384 and sha512

#python-programming #python-tutorials #learn-python #python-project #python3 #python #python-skills #python-tips

How To Compare Tesla and Ford Company By Using Magic Methods in Python

Magic Methods are the special methods which gives us the ability to access built in syntactical features such as ‘<’, ‘>’, ‘==’, ‘+’ etc…

You must have worked with such methods without knowing them to be as magic methods. Magic methods can be identified with their names which start with __ and ends with __ like init, call, str etc. These methods are also called Dunder Methods, because of their name starting and ending with Double Underscore (Dunder).

Now there are a number of such special methods, which you might have come across too, in Python. We will just be taking an example of a few of them to understand how they work and how we can use them.

1. init

class AnyClass:
    def __init__():
        print("Init called on its own")
obj = AnyClass()

The first example is _init, _and as the name suggests, it is used for initializing objects. Init method is called on its own, ie. whenever an object is created for the class, the init method is called on its own.

The output of the above code will be given below. Note how we did not call the init method and it got invoked as we created an object for class AnyClass.

Init called on its own

2. add

Let’s move to some other example, add gives us the ability to access the built in syntax feature of the character +. Let’s see how,

class AnyClass:
    def __init__(self, var):
        self.some_var = var
    def __add__(self, other_obj):
        print("Calling the add method")
        return self.some_var + other_obj.some_var
obj1 = AnyClass(5)
obj2 = AnyClass(6)
obj1 + obj2

#python3 #python #python-programming #python-web-development #python-tutorials #python-top-story #python-tips #learn-python

Basic Data Types in Python | Python Web Development For Beginners

At the end of 2019, Python is one of the fastest-growing programming languages. More than 10% of developers have opted for Python development.

In the programming world, Data types play an important role. Each Variable is stored in different data types and responsible for various functions. Python had two different objects, and They are mutable and immutable objects.

Table of Contents  hide

I Mutable objects

II Immutable objects

III Built-in data types in Python

Mutable objects

The Size and declared value and its sequence of the object can able to be modified called mutable objects.

Mutable Data Types are list, dict, set, byte array

Immutable objects

The Size and declared value and its sequence of the object can able to be modified.

Immutable data types are int, float, complex, String, tuples, bytes, and frozen sets.

id() and type() is used to know the Identity and data type of the object

a**=25+**85j

type**(a)**

output**:<class’complex’>**

b**={1:10,2:“Pinky”****}**

id**(b)**

output**:**238989244168

Built-in data types in Python

a**=str(“Hello python world”)****#str**

b**=int(18)****#int**

c**=float(20482.5)****#float**

d**=complex(5+85j)****#complex**

e**=list((“python”,“fast”,“growing”,“in”,2018))****#list**

f**=tuple((“python”,“easy”,“learning”))****#tuple**

g**=range(10)****#range**

h**=dict(name=“Vidu”,age=36)****#dict**

i**=set((“python”,“fast”,“growing”,“in”,2018))****#set**

j**=frozenset((“python”,“fast”,“growing”,“in”,2018))****#frozenset**

k**=bool(18)****#bool**

l**=bytes(8)****#bytes**

m**=bytearray(8)****#bytearray**

n**=memoryview(bytes(18))****#memoryview**

Numbers (int,Float,Complex)

Numbers are stored in numeric Types. when a number is assigned to a variable, Python creates Number objects.

#signed interger

age**=**18

print**(age)**

Output**:**18

Python supports 3 types of numeric data.

int (signed integers like 20, 2, 225, etc.)

float (float is used to store floating-point numbers like 9.8, 3.1444, 89.52, etc.)

complex (complex numbers like 8.94j, 4.0 + 7.3j, etc.)

A complex number contains an ordered pair, i.e., a + ib where a and b denote the real and imaginary parts respectively).

String

The string can be represented as the sequence of characters in the quotation marks. In python, to define strings we can use single, double, or triple quotes.

# String Handling

‘Hello Python’

#single (') Quoted String

“Hello Python”

# Double (") Quoted String

“”“Hello Python”“”

‘’‘Hello Python’‘’

# triple (‘’') (“”") Quoted String

In python, string handling is a straightforward task, and python provides various built-in functions and operators for representing strings.

The operator “+” is used to concatenate strings and “*” is used to repeat the string.

“Hello”+“python”

output**:****‘Hello python’**

"python "*****2

'Output : Python python ’

#python web development #data types in python #list of all python data types #python data types #python datatypes #python types #python variable type