I am puzzled by the following behavior. I have Python 3.4 installed on Windows 7. Pip came installed with the Windows distribution.
When I try to install virtualenv (or any other package), or execute any other command, nothing happens:
C:\Python34\pip install virtualenv
(nothing happens)
C:\Python34\pip list
(nothing happens)
However, the python -m variants do work.
C:\Python34\python -m pip install virtual env
C:\Python34\python -m pip list
I know that the Python Packaging User Guide, in the section Installing Packages says to use python -m pip install [package name]. However, should 'pip install [package name]' also work?
I found in a previous post that they do the same things, so why is there a difference in behavior?
pip is installed into Scripts subdir.
Try C:\Python34\Scripts\pip -V to see what you are running.
C:\>C:\Python34\Scripts\pip -V
pip 7.1.2 from C:\Python34\lib\site-packages (python 3.4)
Otherwise your pip.exe process might be blocked by the running antivirus.
(Building on Radek's answer) There are two problems with using pip (and similar scripts in Scripts). The first is enabling the OS to find the file. You must either give the correct absolute path or .../Pythonxy/Scripts must be on the PATH. I believe making the latter true is optional when installing.
If you actually entered what you posted, I am surprised that Windows did not respond with the Win 7 version of "c:\programs\python35\pip is not recognized as an internal or external command, operable program or batch file." (from my Win 10 machine).
The second, when more than one version of Python is installed, is the ambiguity of which pip to run (with which python binary). Even if all Python installations have the same pip version, it must be run with the version whose site-packages directory is the intended target. Even when pip install xyz at the command line runs, it may or may not do what is intended.
The dependable solution to both issues is to specify a particular python binary (whether with .../python.exe, python, python2, python3, or py -x.y, and let that binary find 'its' pip and point it to the 'right' site-packages.
Related
I am doing this project where i need to install a package called Twint.
I want to install this package and use it's commands in my VS Code.
What happends when i for example type this in my Windows CMD?
pip3 install --user --upgrade git+https://github.com/twintproject/twint.git#origin/master#egg=twint
Because i can't type this in my VS code terminal, where i usually install packages with pip.
It will return an error that says ERROR: Cannot find command 'git' - do you have 'git' installed and in your PATH?''
Now if i run this in my Windows Command it seems that i can't directly import the package in VS code?
Can anyone help me out with this confusion, where does the files get stored and how do i create good habbits around installing packages?
Hope someone understands what im struggeling with here.
Best
It is often the case that computers have more than one version of python installed and that editors like VS code use a different version than pip uses on the command line. pip installs packages where the version of python it is linked to expects them to be, but VScode doesn't know to look there.
It sounds like you have git installed where pip installs things, so you can upgrade from the command line without issue, but there's no installation of git where VScode is looking, so there's nothing to upgrade.
You either need to find where pip installs things and add it to the $PATH VScode uses, or try running a variation of python -m pip install --user git (specifying a specific url, or other things, as needed) from within VScode, which will ensure the package gets installed in a place that VScode looks for packages.
Download and Install git in your windows from here:
https://git-scm.com/download/win
Then add its installation bin path to your windows's environment path. Then you will find the git command at the command prompt globally.
This may solve you problem.
This question already has answers here:
pip or pip3 to install packages for Python 3?
(10 answers)
Closed 2 years ago.
Eventually, every single time I install a new Linux distribution I do sudo apt-get install python3.
However, once installed I always get confused. python is Python 2.7 and python3 is Python 3.x. But also it appears that pip is for Python 2 and pip3 for Python 3. That said most tutorials I see on Internet always use the traditional pip install even though it is about Python 3.
How should I deal with this? Should I simply continue to put this annoying 3 every time I use Python (pip3, ipython3, python3...)? In most of my lectures I read that creating a symlink python->python3 is a bad practice. Is that correct?
Use python3 -m pip or python -m pip. That will use the correct pip for the python version you want. This method is mentioned in the pip documentation:
python -m pip executes pip using the Python interpreter you specified as python. So /usr/bin/python3.7 -m pip means you are executing pip for your interpreter located at /usr/bin/python3.7.
Symlinking python->python3 is a bad idea because some programs might rely on python being python 2. Though, I have seen some Dockerfiles symlink python->python3, like TensorFlow's CPU dockerfile (it's less of an issue in a Docker image). Coincidentally, that same Dockerfile uses the python3 -m pip install syntax that I recommend.
creating a symlink python->python3 is a bad practice. Is that correct?
Sometimes. Some OSs (looking at you, macOS) deeply rely on python pointing to a Python 2 interpreter for internal tools and tasks. Deleting the shipped Python 2 interpreter (or aliasing python to a Python 3 interpreter) will break stuff. How to uninstall Python 2.7 on a Mac OS X 10.6.4?
Whether the correct command for Python 3 is pip or pip3 or (say) gaschplutzga depends on a number of factors.
If you only have Python 3, and you have a command named pip, that's probably safe to use. Going forward, this will be the simple, obvious, safe answer in more and more places.
If you have both, and there is a command called pip3 installed on your system, probably that's the correct one to use.
More generally, you can go through your PATH and look for commands with suitable names. On Unix-like systems with a POSIX-compatible shell, try the commands command -V pip3 and command -V pip. (On Windows systems, maybe try where pip3 and where pip, or pray to whatever dark deity informed your choice of operating system.)
If you receive output like
/opt/random/nonstandard/whoa/pip
/usr/local/bin/pip
/usr/bin/pip
you can try each of these in turn with the full path and adding the --version option to have them identify themselves. When you specify the full path, you are bypassing the system's PATH mechanism entirely. For example,
/opt/random/nonstandard/whoa/pip --version
might identify itself as belonging to Python version 3.2.1. If that's the one you want, and it's at the top of your PATH, you can simply rely on the PATH to give you this version when you type just pip. If not, perhaps you can shuffle your PATH (but understand that this changes the resolution order for all commands in the directory whose position you change) or create a simple alias or wrapper which bypasses the PATH for this particular command in your personal account. On Unix-like systems with a POSIX-compatible shell, this might look like
alias pip=/opt/random/nonstandard/whoa/pip
(to persist this across sessions, you'd add this to your .profile or similar - for Bash, try .bash_profile if it exists; for Zsh, try .zshrc. The full scoop for each shell is more complicated than I can squeeze into these narrow parentheses); on Windows, you might be able to control this by setting the environment variable PY_PYTHON, but there's a huge can of worms behind that "might".
Some sites and OSes / distros have additional wrappers or conventions which introduce additional options; if you use a specific package manager, perhaps also study its documentation. (One common example is Anaconda, though I don't believe it affects the naming or location of pip specifically.)
Use virtual environments, then pip would be associated with the python used to create that virtual environment. Whether you use pip or pip3, it will be equivalent to python3 -m pip as mentioned in jakub's answer. Also, given that Python 2.7 is already EOL (which means you will most likely work with Python 3) and that pip install-ing things onto the system packages should be avoided, then a virtual environment would be helpful here.
For example, using pipenv:
$ pipenv --python=/usr/local/opt/python#3.8/bin/python3
$ pipenv shell
Launching subshell in virtual environment...
(TEMP) $ pip --version
pip 20.2.3 from /Users/me/.venvs/temp2-SbXvZiFd/lib/python3.8/site-packages/pip (python 3.8)
(TEMP) $ pip3 --version
pip 20.2.3 from /Users/me/.venvs/temp2-SbXvZiFd/lib/python3.8/site-packages/pip (python 3.8)
For example, using venv:
$ python3.8 -m venv .venv
$ source .venv/bin/activate
(.venv) $ pip --version
pip 20.2.3 from /Users/me/temp2/.venv/lib/python3.8/site-packages/pip (python 3.8)
(.venv) $ pip3 --version
pip 20.2.3 from /Users/me/temp2/.venv/lib/python3.8/site-packages/pip (python 3.8)
The virtual environment takes care of making sure pip or pip3 in this env refers to the pip from the correct Python version. You can then happily follow tutorials that still use pip install something (unless of course that tutorial refers to a Python 2.7 or a system-wide installation).
You can install pip through pip3 and this should resolve this issue.
$ pip --version
pip 19.0.3 from /usr/local/lib/python2.7/dist-packages/pip (python 2.7)
Notice that pip here is of Python 2.7 (in this example).
You can then force pip3 of Python 3.X to install pip under itself.
$ sudo pip3 install pip --upgrade
Installing collected packages: pip
Found existing installation: pip 8.1.1
Not uninstalling pip at /usr/lib/python3/dist-packages, outside environment /usr
Successfully installed pip-19.0.3
Once you check this again, it should reference Python 3.X so you don't have to deal with
what is what.
$ pip --version
pip 19.0.3 from /usr/local/lib/python3.5/dist-packages/pip (python 3.5)
I doubt you'll want to use Python 2 after this, but if you do happen to work with Python 2 code, you can create a virtual environment to access those commands again. Otherwise, you won't have to worry about the pip or pip3 distinction after this.
Not really a duplicate of this question, but this helped me suggest this answer: Can pip (python2) and pip3 (python3) coexist?
Pip is for python version less than 3. and pip3 is used when you want to install packages for python version 3 or higher.
I need to work with Both Python 2.7.12 and python 3.5.2 simultaneously on my Ubuntu 16.04.1 LTS. Python 3 came pre-installed so I've no idea where it sits, in terms of path to the directory, while python 2 sits in /usr/local/lib/python2.7/.
I found lots of questions on SO and on askubuntu about how to install but nothing about how to use them separately, installing different libraries, and what should I avoid or be careful of, if I maintain this dual python thing for the long term? For example, I usually run pip install to install a library and I can check that its installed in my python2 directory but how do I install the same package for my python3 without conflicts? Something like: python3 pip install <package> ?? Where is the default python3 installed? And how do I call python3 for paths where python is not part of the command for example: pip freeze, sudo-apt get, etc.?
PS: I've not officially worked with Virtualenv but I've been informed that is usually good for isolating projects within a python language version, rather than isolating two different language versions from each other.
Please let me know.
Thanks
This is absolutely no problem, as Python does that for you. You don't need a virtualenv at all.
If you use Ubuntu packages, make sure you use the python3- versions for Python 3, and the normal python- versions for Python 2.
For example, python3-numpy and python-numpy.
If you use pip to install extra packages, you an either use the pip script with the version number appended: pip2.7 or pip3.5, or, my preferred method, call pip as a module for the respective Python executable:
python2.7 -m pip install <whatever>
and
python3.5 -m pip install <whatever>
Other than that, there should not be any issue: Python stores the packages in completely separate directories, and each Python executable only uses its respective directive.
Do not fiddle around with PYTHONPATH, unless you really know what you're doing. This has the danger of setting your PYTHONPATH to a directory with Python 2.7 modules and then using Python 3.5 to run things.
If you start from scratch, you may need to install pip first.
For the system Python(s), use the relevant package:
sudo apt install python-pip
sudo apt install python3-pip
For your locally installed Python(s), use the built-in bootstrapper module:
pythonx.y -m ensurepip
Note on the OS-installed Python executables:
Python 3.5 lives at /usr/bin/python3.5, Python 2.7 (the OS one) at /usr/bin/python2.7.
You could even use the OS 2.7 one next to your locally installed /usr/local/bin/python2.7 (and confuse yourself when a package can't be found because you used the wrong one).
Or install Python 3.6 next to Python 3.5 (provided you've used make altinstall, so python3 doesn't get overwritten).
This is also why you don't really want to run pip (or even pip2.7) as is: pip2.7 may get you the system one, instead of the one in /usr/local/bin/pip2.7, depending on your PATH.
(The same goes for the python2.7 executable, so if you need to specify the full path /usr/local/bin/python2.7 to run that one (or have an alias), the same holds for pip2.7. If, on the other hand, /usr/local/bin is first on your PATH, you should in principle never run into the same pip and python executables.)
I am using tox to manage some testing environments. I have a dependency (backports.ssl-match-hostname) that I cannot download using the latest version of pip, so I need to revert back to pip 8.0.3 to allow the install to work.
I have included the 8.0.3 version of pip inside my tox.ini file for dependencies.
deps=
pip==8.0.3
However, when I run
source .tox/py27/bin/activate
and enter the virtual testing environment, and then run
pip --version
I end up with
8.1.2
However, outside of my tox environment, when I run the same command, I get
8.0.3
Is there anything special that tox does when grabbing pip? Why am I not able to specify the version of pip that I want to use as a dependency?
EDIT : to add to this, it seems as though I am able to grab the dependency pip==8.0.3, but for the other dependencies, they are still running from the command launched with pip==8.1.2
So, I need to be able to grab pip==8.0.3 first, and then once installed, grab everything else. Still unsure why tox is starting with pip==8.1.2
This was apparently the result of the "virtualenvs" python package containing a pre-selected group of python packages that it refers to, one of which was the latest and greatest pip.
I don't know if this is the preferred way of doing this, but I found success by running
pip uninstall virtualenv
And then reinstalling with the version that worked
pip install virtualenv==15.0.1
With the "correct" version of virtualenv in place, I was able to run my tox command
source .tox/py27/bin/activate
and see the desired version of pip
pip --version
pip 8.0.3
A workaround for this is here: https://github.com/pypa/pip/issues/3666
Although to make it work I had to write "pip install pip==8.1.1" in my script. So to recap:
Add a pip.sh script to your project:
#!/bin/bash
pip install pip==8.1.1
pip install "$#"
Add to your tox.ini:
install_command = {toxinidir}/pip.sh {opts} {packages}
I've recently hit this problem. I've had it for a while but it just didn't register because I had such occasional failures with Python 2/3 code. Another way that this can happen is, if like me, you change the virtualenv between different Python versions and don't clean up.
Check /bin or /Scripts to see whether python2 points to python. If the virtualenv is Python 3 then this will mean that python2 actually calls Python 3. Vice versa, of course, if you the virtualenv is Python 2 and you want to test Python 3 code.
New versions of virtualenv reach out to download the latest pip, setuptools, and wheel -- you can disable this behavior when running through tox with the tox-virtualenv-no-download package See: https://github.com/asottile/tox-virtualenv-no-download#wait-why
What is a way to instaill python modules within cygwin? I'm new to cygwin and couldn't find pip or anything like that in the setup.exe package. I've looked around and I can't find a definitive way to do it. Does anyone have advice?
On windows, under cygwin follow the below steps.
1.Ensure python is installed in cygwin. Type python on the terminal of cygwin and it should launch the python shell. If it doesn't launch the setup file for cygwin and select python from the package list and install.
2. Now, install pip if it's not already installed. Provide full path if you have multiple python installations e.g.
/usr/bin/python2.7 -m ensurepip
/usr/bin/python3.6 -m ensurepip
3. Now, you can use pip to install the python package. Depending upon the installation in which you want the package to be installed, run below command(s)
/usr/bin/python2.7 -m pip install pyyaml
/usr/bin/python3.6 -m pip install pyyaml
In standard python installation, pip like scripts goes under "your_python_directory\Scripts". (in my system C:\Python34\Scripts) Make sure you have added this path to system directories (Environment Variables). Then
pip.exe install my_package_name
will work fine.
Also for configuring within cygwin this will help.
PS: sorry for confusion though I thought you meant you have installed python separately from cygwin. I believe this thread answers your question.
I would suggest installing the python in windows.
Suppose you install the python in D drive, then just call the installed python from cygwin like
/cygdrive/d/Python37/python.exe
In this case, you would not get two versions of python (one in cygwin, one in windows). And you can call the python from other terminals as well.