This document aims to give an overview of Windows-specific behaviour you should know about when using Python on Microsoft Windows.
Unlike most Unix systems and services, Windows does not include a system supported installation of Python. These installers are primarily intended to add a per-user installation of Python, with the core interpreter and library being used by a single user.
The installer is also able to install for all users of a single machine, and a separate ZIP file is available for application-local distributions. As specified in PEP 11a Python release only supports a Windows platform while Microsoft considers the platform under extended support. This means that Python 3. If you require Windows XP support then please install Python 3.
There are a number of different installers available for Windows, each with certain benefits and downsides. The full installer contains all components and is the best option for developers using Python for any kind of project. The Microsoft Store package is a simple installation of Python that is suitable for running scripts and packages, and using IDLE or other development environments. It requires Windows 10, but can be safely installed without corrupting other programs. It also provides many convenient commands for launching Python and its tools.
The nuget. It can be used to build Python packages or run scripts, but is not updateable and has no user interface tools.
The embeddable package is a minimal package of Python suitable for embedding into a larger application. Four Python 3. The web installer is a small initial download, and it will automatically download the required components as necessary. The offline installer includes the components necessary for a default installation and only requires an internet connection for optional features. See Installing Without Downloading for other ways to avoid downloading during installation.
You will not need to be an administrator unless a system update for the C Runtime Library is required or you install the Python Launcher for Windows for all users. The Python Launcher for Windows will be installed according to the option at the bottom of the first page. If selected, the install directory will be added to your PATH.
To install debugging symbols or binaries, you will need to use this option. The Python Launcher for Windows will be installed into the Windows directory. If selected, the install directory will be added to the system PATH. Windows historically has limited path lengths to characters.
This meant that paths longer than this would not resolve and errors would result. In the latest versions of Windows, this limitation can be expanded to approximately 32, characters.
This allows the open function, the os module and most other path functionality to accept and return paths longer than characters when using strings. Use of bytes as paths is deprecated on Windows, and this feature is not available when using bytes. Changed in version 3. All of the options available in the installer UI can also be specified from the command line, allowing scripted installers to replicate an installation on many machines without user interaction.
These options may also be set without suppressing the UI in order to change some of the defaults. The full list of available options is shown below. Compile all. Install python. Install Python Launcher for Windows. Installs Python Launcher for Windows for all users. For example, to silently install a default, system-wide Python installation, you could use the following command from an elevated command prompt :.Until the release of Python 3.
Even though 3. This essay only officially covers Python versions back to Python 2. As with all my essays on this site, suggestions for improvement or requests for clarification can be posted on BitBucket. Prior to Python 3. This has changed in Python 3. Where foo. With that layout and the current working directory being projectPython 2. This is an all new trap added in Python 3. This happens even if there are other preceding subdirectories on sys.
This complexity is primarily forced on us by backwards compatibility constraints - without it, some existing code would have broken when Python 3. However, it is also useful in that it makes it possible to explicitly declare that a package is closed to additional contributions.
This next trap exists in all current versions of Python, including 3. The reason this is problematic is that every module in that directory is now potentially accessible under two different names: as a top level module since the directory is on sys.
As an example, Django up to and including version 1. This is a recipe for confusion if there is any meaningful mutable module level state, so this behaviour was eliminated from the default project layout in version 1. Unfortunately, this is still a really easy guideline to violate, as it happens automatically if you attempt to run a module inside a package from the command line by filename rather than using the -m switch. Note that if the project exclusively uses explicit relative imports for intra-package references, the last two commands shown may actually work for Python 3.
For a long time, the only way to get sys. This last approach is actually how I prefer to use my shell when programming in Python - leave my working directory set to the project directory, and then use the -m switch to execute relevant submodules like tests or command line tools. The fact that most methods of invoking Python code from the command line break when that code is inside a package, and the two that do work are highly sensitive to the current working directory is all thoroughly confusing for a beginner.
I personally believe it is one of the key factors leading to the perception that Python packages are complicated and hard to get right.
However, even if there are improvements in this area in future versions of Python, this trap will still exist in all current versions.
That way, inadvertently executing the main module twice becomes harmless. Keeping main modules small and simple also helps to avoid a few potential problems with object serialisation as well as with the multiprocessing package. Another common trap, especially for beginners, is using a local module name that shadows the name of a standard library or third party package or module that the application relies on. It turns out this is a really bad idea, as using such a name means the Python interpreter can no longer find the real socket module in the standard library, as the apparent socket module in the current directory gets in the way:.
Following on from the example in the previous section, suppose we decide to fix our poor choice of script name by renaming the file. In reality, what has happened is that the cached bytecode file from our previous failed import attempt is still present and causing trouble, but when Python tries to display the source line for the traceback, it finds the source line from the standard library module instead.
Removing the stale bytecode file makes things work as expected:. This particular trap has been largely eliminated in Python 3.See Alternate Implementations for further resources.
How To Install PIP to Manage Python Packages in Linux
The interpreter interface resembles that of the UNIX shell, but provides some additional methods of invocation:. When called with a file name argument or with a file as standard input, it reads and executes a script from that file.
When called with a directory name argument, it reads and executes an appropriately named script from that directory. When called with -c commandit executes the Python statement s given as command.
Here command may contain multiple statements separated by newlines. Leading whitespace is significant in Python statements! When called with -m module-namethe given module is located on the Python module path and executed as a script. An interface option terminates the list of options consumed by the interpreter, all consecutive arguments will end up in sys.
Execute the Python code in command. If this option is given, the first element of sys. Raises an auditing event cpython. Search sys. Since the argument is a module name, you must not give a file extension. The module name should be a valid absolute Python module name, but the implementation may not always enforce this e.
Package names including namespace packages are also permitted. This behaviour is deliberately similar to the handling of directories and zipfiles that are passed to the interpreter as the script argument. This option cannot be used with built-in modules and extension modules written in C, since they do not have Python module files. However, it can still be used for precompiled modules, even if the original source file is not available.
As with the -c option, the current directory will be added to the start of sys. Many standard library modules contain code that is invoked on their execution as a script. An example is the timeit module:.
PEP — Executing modules as scripts. Changed in version 3. Read commands from standard input sys.See Alternate Implementations for further resources. The interpreter interface resembles that of the UNIX shell, but provides some additional methods of invocation:.
An interface option terminates the list of options consumed by the interpreter, all consecutive arguments will end up in sys. Execute the Python code in command. If this option is given, the first element of sys.
Search sys. Since the argument is a module name, you must not give a file extension. The module-name should be a valid Python module name, but the implementation may not always enforce this e. This option cannot be used with built-in modules and extension modules written in C, since they do not have Python module files. However, it can still be used for precompiled modules, even if the original source file is not available.
As with the -c option, the current directory will be added to the start of sys. Many standard library modules contain code that is invoked on their execution as a script. An example is the timeit module:.How to Install Python on Windows and run in cmd (solved)
PEP — Executing modules as scripts. Changed in version 2. Read commands from standard input sys. If standard input is a terminal, -i is implied. If the script name refers directly to a Python file, the directory containing that file is added to the start of sys. If the script name refers to a directory or zipfile, the script name is added to the start of sys.
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I made a twitter bot using Python which uses the tweepy module. I then converted the Python file into an. If I run the program in Powershell as the Python file it all works but when I try to run the. I've already tried uninstalling and reinstalling tweepy again but I keep on getting the same error. Does anyone know how to fix this? Sometimes automatic dependency detection doesn't work. Learn more. Asked 2 years, 8 months ago.
Active 2 years, 8 months ago. Viewed times. Vesper DougCoburn No. In the setup. DougCoburn Would I have to somehow add it in? I'd give it a try: cx-freeze.
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It only takes a minute to sign up. My default Python binary is set to the one with the Anaconda distribution of Python.
If I run this by entering python test. But when I open test. So my question is: Why can PyCharm not find the caffe module when it runs the Python script, but it can be found when I run the script from the terminal? As ByteCommander said in a comment, PyCharm doesn't use bashrc, so it doesn't know where your library is.
In the same screen where you added the interpreter you can see a wheel icon, click it, it will show you a menu, click on more. You should see a screen like this:. Programs started from the Ubuntu launcher do not read.
As an alternative to setting the paths in PyCharm, you can simply start PyCharm from a Bash shell to give it access to the environment variables you set in. Now close the IDE and open it again. Ubuntu Community Ask! Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Asked 4 years, 6 months ago. Active 1 year, 7 months ago. Viewed 59k times. Now, I have a simple Python file, called test.
Thank you! Karnivaurus Karnivaurus 2 2 gold badges 11 11 silver badges 30 30 bronze badges. I guess PyCharm does not care about your. You have to set that variable either in PyCharm or in e. Active Oldest Votes.
You should see a screen like this: You should select your interpreter and click on the last button.Python command-line arguments are the parameters provided to the script while executing it. The command-line arguments are used to provide specific inputs to the program. Python command-line arguments help us to keep our program generic in nature. For example, we can write a program to process a CSV file.
This will make our program loosely coupled and it will be easy to maintain it. Another benefit of command-line arguments is the additional security that comes with it.
If we store the database credentials in the script or some configuration file, it can be accessed and executed by anyone having access to the files. If you are running the python script from the terminal, just pass the arguments after the script name. The arguments are separated with white space characters. The command-line arguments are stored in the sys module argv variable, which is a list of strings.
We can read the command-line arguments from this list and use it in our program. Note that the script name is also part of the command-line arguments in the sys. Python getopt module works in a similar way as the Unix getopt function. This module is helpful when you want the script to accept options and their values, similar to the many Unix commands. This module works in conjunction with the sys.
Python Command Line Arguments – 3 Ways to Read/Parse
We can use Python argparse module also to parse command-line arguments. There are a lot of options with argparse module. If your script requires simple command-line arguments, you can go with sys. But, if your program accepts a lot of positional arguments, default argument values, help messages, etc, then you should use argparse module.
I have been working on Python for more than 5 years. I love the simplicity of the language and the plethora of libraries in all the different areas of development. Generic selectors. Exact matches only. Search in title. Search in content.
Search in excerpt. Search in posts. Search in pages. Prev Python ternary Operator Examples. AskPython I have been working on Python for more than 5 years. Get Latest Updates on AskPython.