I am very new to Python programming. I can use pip install without any trouble. I've seen a lot of posts in online which prefix pip install with python -m. When I use python -m before the pip command nothing seems to happen. Please explain.
If you run python -h, the -m flag is described as:
-m mod : run library module as a script (terminates option list)
In this case, when you run python -m pip Python runs the pip module as a script (i.e. it executes the code inside it). If you have added pip to your PATH you can then just run pip directly without the need to invoke it via python.
python -m pip install <some module> and pip install <some module> should perform identically. If you have multiple versions of Python installed on your system, using pip might install a module for the wrong version of Python. You can check the version using pip -V which will output something like
pip 18.1 from /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pip (python 3.7)
here the python version is python3.7.
If the version of the pip command doesn't match with the version of Python used to execute a program when the program is executed it will not run. You can check your Python version with python -V, which will output something like
Python 2.7.16
If the pip version doesn't match your Python version you can either update your path's pip, or you can use python -m pip. To select the correct version (i.e. if python runs Python 2 and you want to use Python 3) just execute python3 -m pip or python3.7 -m pip.
Related
I'm trying to create a database with mongodb and python and I installed pymongo library with the following command:
sudo pip3 install pymongo
But when trying to run the application, the error appears stating that pymongo is not installed:
pymongo error
I use VS Code to program in Python and the python interpreter is located at /home/paulo/Python-3.8.2
But pymongo was installed in this location, but I didn't select it
You have multiple versions of python installed. It is installing to python3.7 instead of the 3.8 you are using.
You can force it to install to your default python environment (which should be 3.8) by using sudo python -m pip install pymongo. I cannot tell if you're using macOS or linux. if you're using linux you can also typically use sudo python3.8 -m pip install pymongo.
This will let you run the pip command with your default python command install.
Using -m will let you use that default python version to run pip instead of the one set in your ~/.bashrc file.
Alternatively you can go into your ~/.bashrc file and change the pip3 alias to the correct version of python. You can find the correct version by using which python which will give you the location of your default python install.
I can't seem to find an answer or solution to this anywhere so if there is one please quote or link it here. When running python in the command line, if I do python3 -m pip install aiohttp it installs aiohttp just fine. However, if I do py -m pip install aiohttp it gives me install errors because it seems to have trouble "building wheel" and I have no idea why.
You might have multiple python 3 versions installed.
Wheel might be in one but not the other version.
py uses the latest version installed. python3 might not.
In cmd, type each command separately, in the first lines it will display the python version each command is using.
python3 and py are different things, python3 is calling the python3 third-party library then after access it then -m then call pip module so it’s python3 -m pip then what we need to do is installing packages so it’s install then type what you need :)
so the whole command:
python3 -m pip install aiohttp
I am using Windows 10. Currently, I have Python 2.7 installed. I would like to install Python 3.5 as well. However, if I have both 2.7 and 3.5 installed, when I run pip, how do I get the direct the package to be installed to the desired Python version?
You will have to use the absolute path of pip.
E.g: if I installed python 3 to C:\python35, I would use:
C:\> python35\Scripts\pip.exe install packagename
Or if you're on linux, use pip3 install packagename
If you don't specify a full path, it will use whichever pip is in your path.
Because usually i change my intepreter to run something(i got 2 diff projects with both 2 and 3), i use these solution:
Add path to the environment as usual (of course)
Rename ur python.exe , in my case i want to run python 3 using command python3 on my cmd. So i renamed my python.exe in python3.x directory with python3. Itll works with python 2 ofc.
Then to use pip in both python, i use this command.
python3 -m pip install 'somepackage'
and to run pip on python2
python -m pip install 'somepackage'
This is may not the best solution out there, but i like this one
** WINDOWS **
ref : https://datascience.com.co/how-to-install-python-2-7-and-3-6-in-windows-10-add-python-path-281e7eae62a
In my case, I have Python 2.7 and Python 3.4, with the Python Launcher for Windows.
This is the output when running this commands:
PS C:\> pip -V
pip 9.0.1 from c:\python27\lib\site-packages (python 2.7)
PS C:\> pip3 -V
pip 9.0.1 from C:\Python34\lib\site-packages (python 3.4)
I'll note that in my Python27\Scripts\ directory, I have pip.exe, pip2.exe and pip2.7.exe.
And in my Python34\Scripts\ directory, I have pip.exe, pip3.exe and pip3.4.exe.
So all of these .exe files help you when you have different versions of Python installed at the same time.
Of course, for this to work, you have to have the respective Scriptsdirectries in your Path system enviroment variable.
The answer from Farhan.K will work. However, I think a more convenient way would be to rename python35\Scripts\pip.exe to python35\Scripts\pip3.exe assuming python 3 is installed in C:\python35.
After renaming, you can use pip3 when installing packages to python v3 and pip when installing packages to python v2. Without the renaming, your computer will use whichever pip is in your path.
I would advise against ever calling any pip script directly (nor pip3, pip2.7.exe, anything like that).
Instead, a surefire way is to always prefer the explicit variant of calling pip's executable module for a specific Python interpreter:
path/to/pythonX.Y -m pip somecommand
path/to/venv/bin/python -m pip somecommand
C:\path\to\venv\Scripts\python.exe -m pip somecommand
There are many advantages to this, for example:
It is explicit for which Python interpreter the projects will be pip-installed (Python 2 or 3, inside the virtual environment or not, etc.)
For a virtual environment, one can pip-install (or do other things) without activating it: path/to/venv/bin/python -m pip install SomeProject
Under Windows this is the only way to safely upgrade pip itself path\to\venv\Scripts\python.exe -m pip install --upgrade pip
But yes, if all is perfectly setup, then python3 -m pip install SomeProject and pip3 install SomeProject should do the exact same thing, but there are way too many cases where there is an issue with the setup and things don't work as expected and users get confused (as shown by the many questions about this topic on this platform).
References
Brett Cannon's article "Why you should use python -m pip"
pip's documentation section on "Upgrading pip"
venv's documentation section on "Creating virtual environments": "You don’t specifically need to activate an environment [...]"
I ran across an issue with running pip with absolute path. This might be related to WinPython's installation routine and the order of installing Python 3.6 first, 2.7 second, or Python 3.6 being in the path.
No matter which pip was called, it was activating the 3.6 one:
λ C:\prog\WinPython-64bit-2.7.13.1Zero\python-2.7.13.amd64\Scripts\pip2.exe --version
pip 9.0.1 from C:\prog\WinPython-64bit-3.6.1.0Zero\python-3.6.1.amd64\lib\site-packages (python 3.6)
What finally did the trick was calling pip as a module of the respective python binary:
λ C:\prog\WinPython-64bit-2.7.13.1Zero\python-2.7.13.amd64\python.exe -m pip --version
pip 9.0.1 from C:\prog\WinPython-64bit-2.7.13.1Zero\python-2.7.13.amd64\lib\site-packages (python 2.7)
Hope that might help someone with similar issues.
I tried many things , then finally
pip3 install --upgrade pip worked for me as i was facing this issue since i had both python3 and python2.7 installed on my system.
mind the pip3 in the beginning and pip in the end.
And yes you do have to run in admin mode the command prompt and make sure if the path is set properly.
1-open command prompt and change direction using the command cd C:\Python35\Scripts
2- write the command pip3 install --upgrade pip
3- close the command prompt and reopen it again to return to the default direction and use the command pip3.exe install package_name to install any package you want
Having a weird problem with pip on os x.
As far as I can recall (and a quick look at my .bash_history seems to confirm) I have not made any recent changes to my configuration. Alas, the pip command seems to be suddenly using a different version of python than it was previously. Up until now I was using the command pip to manage my python2 libraries and pip3 to manage by python3 libraries. Suddenly, any attempts at running pip install fails with errors like missing parenthesis around print statements.
Here is the result of a few commands I attempted to figure out the problem:
which pip > /usr/local/bin/pip
which pip3 > /usr/local/bin/pip3
which python > /usr/local/bin/python
python version > Python 2.7.11
pip --version > pip 8.1.1 from /usr/local/lib/python3.5/site-packages (python 3.5)
So for some reason the pip command seems to be running from the PyPi2 database but in python3 now? Any ideas how to fix this?
I run with multiple Python versions and thus multiple pip versions as well.
Everytime, however, you update pip, you'll replace the standard pip command with the version you updated. So even pip3 install --upgrade pip will put a /usr/local/bin/pip in your system, messing up the Python 2 version.
Instead, I run pip as an (executable) module:
python3 -m pip search <package>
or
python2 -m pip search <package>
or even
python3.5 -m pip search <package>
This guarantees that your pip version always matches the Python version you want to use it for. It's somewhat longer to type, but I prefer the expliciteness of it (which, I guess, follows the Zen of Python).
Note that updating pip:
python3.5 -m pip install --upgrade pip
will still install a Python 3.5 version in /usr/local/bin/pip, but I'm simply ignoring that. Just beware of (shell) scripts that execute pip directly.
Find absolute path to Python you'd like to use:
which python
Open your default pip executable script:
vi $(which pip)
You will see a shebang line at the top which may point to wrong Python (i had that once too).
Point to the Python you want (see step 1), e.g.:
#!/usr/local/bin/python3.7
Try setting aliases by running the following commands in Terminal,
alias pip="/usr/local/bin/pip"
alias pip2="/usr/local/bin/pip"
alias pip3="/usr/local/bin/pip3"
If this solves your problem then you need to add the aliases in your bash profile.
Look How do I create a Bash alias? for more info.
Alternatively, you have to reinstall pip using python2 get-pip.py first and then python3 get-pip.py get-pip.py can be downloaded here https://bootstrap.pypa.io/get-pip.py
I had exactly the same problem!
I reinstall python2 by brew brew reinstall python#2
after reinstall, pip install packagename works!
None of these worked for me so what I did was navigate to
C:\Users(User)\AppData\Local\Programs\Python\
and deleted all the old python versions I wasn't using. (Worked)
I am very new to the world of coding, so I will try to provide as much information as i can regarding to my question.
Essentially, I wanted to install a module (moviepy) for Python 3. The site were I found the module suggested I use pip to unpack and install the module, so I did.
In my terminal, I entered pip install moviepy and pip proceeded to unpack and install my module, yay!
I then went over to my IDLE to see if the module would import, import moviepy, but received this error:
ImportError: No module named 'moviepy'
Huh? I thought I had just installed moviepy?
Upon further investigation, the module appears to have been written to my Python 2.7 site-packages folder and not my in Python 3 site-packages folder.
So my question is: How can I get my module to install to Python 3?
The modules website says that it is compatible with Python 3.
Im assuming this is a file path issue of some kind, but i don't know where to begin.
I'm currently using a OS X Yosemite version 10.10.2, Python 2.7.6, Python 3.5.0
Any help or comments are greatly appreciated here!
Help the n00b!
If you are using python in linux you must run pip with python3:
python3 -m pip install moviepy
according to python official doc :
On Linux, Mac OS X and other POSIX systems, use the versioned Python
commands in combination with the -m switch to run the appropriate copy
of pip:
python2 -m pip install SomePackage # default Python 2
python2.7 -m pip install SomePackage # specifically Python 2.7
python3 -m pip install SomePackage # default Python 3
python3.4 -m pip install SomePackage # specifically Python 3.4
Since pip itself is written in python , you could simply run the following in your terminal:
/path/to/python3 /usr/bin/pip install foo
More info:
To install pip, securely download get-pip.py
Run the following (which may require administrator access):
/path/to/python3 get-pip.py
Try below version of moviepy
pip install moviepy==0.2.3.5