如何在 Python 命令中實現 Python Shebang

在本主題中,我們將討論 Python shebang 是什麼以及它是如何在 Python 命令中實現的。

shebang 是腳本文件中的唯一字符序列,用#! 表示。通過指示應調用的程序類型,有助於指定應如何運行整個腳本。每個文件行都以 shebang 字符序列開頭。

此外,該序列通過 shebang 字符後跟程序地址來提供程序的位置。

Shebangs 允許開發人員直接調用腳本。如果 shebang 不存在,您別無選擇,只能手動運行它。

我們如何實現 Python Shebang?

如果您希望運行 Python 3 腳本,請在命令行中輸入以下命令。

#!/usr/bin/env python3

在虛擬環境中工作時建議使用此命令。

您可以根據需要更改 Python 版本。不指定版本表示您的程序可以同時運行 Python 2 和 3。

請注意,這些命令也適用於 Windows 的默認 Python 啟動器。

#!/usr/bin/env python vs #!/usr/local/bin/python

#!/usr/bin/env python#!/usr/local/bin/python
會自動找出 Python 的正確位置。這指定了 Python 可執行文件在您的機器中的位置。腳本的其餘部分需要解釋。
定位後,它將作為整個腳本的默認解釋器。這指向 Python 位於 /usr/local/bin/python。
如果後者失敗,則可以使用此命令。Python 可以安裝在 /usr/bin/python 或 /bin/python 中。在這些情況下,上面的 #! 將失敗。

我們如何在 Python Shebang 中包含參數?

即使命令中可以有參數,大多數操作系統對參數的數量都有限制。Unix 和 Linux 操作系統只支持一個參數。

如果/usr/bin/env命令正在運行。單參數槽已被使用。因此,無法使用上述命令使用參數。但是,解決方案是硬編碼 Python 的絕對路徑,而不是使用/usr/bin/env.

它應該看起來像這樣:

#!/bin/bash -x

執行的行應如下所示:

/bin/bash "-x" /path/to/script

Mac 操作系統上的 Python shebang

在 macOS 中,當您在 shebang 中使用 /bin/bash 的絕對路徑時,您確保將使用內置版本 bash 。對於 macOS 系統管理員,這是推薦的 shebang。這是因為它提供了一個公認的環境。

由於 macOS 是 Unix 發行版,因此提供的參數是相同的。(請參閱本文的標題“我們如何在 Python Shebang 中包含參數? ”)

我們如何在虛擬環境中將 Shebang 用於 Python 腳本?

如果您希望使用位於虛擬環境中的 Python 解釋器,請使用:

#!/usr/bin/env python

此命令將自動找到位於您的虛擬環境中的 Python 解釋器,並將其用於運行 Python 腳本的其餘部分。

在不同平台上運行 Python Shebang

假設您在 Windows 和 Linux 操作系統上運行 Python 腳本。每個操作系統的 shebang 行將是:

Windows
#!C:\Python26\python.exe

Linux Distributions
#!/usr/bin/python

除了在這些命令之間交替使用,我們如何使用一行來為每個分發調用相應的解釋器?

#!/usr/bin/env python

使用這一行將調用env在 PATH 中搜索上述兩個操作系統的 Python可執行文件。

Python Shebang 中的常見錯誤

Bash 腳本權限被拒絕和錯誤的解釋器

對於這個例子,我們有一個調用 Python 腳本及其參數的命令。

#! /bin bash

python CreateDB.py ./MyPath ./MyPath/MySystem/

但是在您的終端中運行它時,您將收到以下錯誤

bash: ./myPath.sh: /bin: bad interpreter: Permission denied

這很可能是因為bin和之間有一個空格字符bash

可以在#!字符後添加空格。它後面應該是 Python 腳本的完整路徑。

正確的實現是:

#! /bin/bash

要不就

#!/bin/bash

Python Shebang 的常見問題

我們如何將 shebang 用於 Anaconda Python 發行版?

假設您的 Python 位於~/anaconda/bin/python. 為了讓腳本被特定的解釋器解釋,它的位置必須指向 after #!

您的命令應如下所示:
#!/home/yourusername/anaconda/bin/python

結論

我們已經演示了 shebang 以及它如何指定應調用的程序。已經解釋了不同操作系統系統上的 Shebang。

來源:  https ://www.pythonpool.com

#python 

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如何在 Python 命令中實現 Python Shebang
Ray  Patel

Ray Patel

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Lambda, Map, Filter functions in python

Welcome to my Blog, In this article, we will learn python lambda function, Map function, and filter function.

Lambda function in python: Lambda is a one line anonymous function and lambda takes any number of arguments but can only have one expression and python lambda syntax is

Syntax: x = lambda arguments : expression

Now i will show you some python lambda function examples:

#python #anonymous function python #filter function in python #lambda #lambda python 3 #map python #python filter #python filter lambda #python lambda #python lambda examples #python map

Shardul Bhatt

Shardul Bhatt

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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

Art  Lind

Art Lind

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

Art  Lind

Art Lind

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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?

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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

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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