I am a beginner in Python, trying to still learn the basics. I am mostly interested in using it for Data Analysis and Visualizations, with packages such as matplotlib.
Most of the examples I see, use the code
"import matplotlib"
or something similar.
But there are also cases when people suggest using pip install the use the package.
So, as a rule of thumb, when should one use import and when should one install through the terminal?
Let's say you want to use some library. Let its name be ABC. ABC has some function, let's say function1.
If you write
import ABC
ABC.function1()
you will get error. Because in your virtual environment python can't find library called ABC. You must install it first using pip install ABC in your terminal. After that same code will work.
You must install library first in order to use it.
There is no thumb rule for using a method to install. You can use any method for installing. Aim is to install so that the library is available when you run the code, else you will get an error.
In Windows, if you want to install a package/library use the following Command on DOS Prompt
python3 -m pip install matplotlib.
To Upgrade the same, use the following Command on DOS Prompt
python3 -m pip install --upgrade matplotlib.
You can install and upgrade the package/libraries through Jupyter too.
Once installed, you need to place the import <library_name> on top of the code in which you want to use that library.
Related
I have a Python library (https://github.com/jcrozum/PyStableMotifs) that I want to publish on PyPI. It depends on another library (https://github.com/hklarner/PyBoolNet) that I do not control and that is only available on GitHub, and in particular, it is not available on PyPI. My setup.py looks like this:
from setuptools import
setup(
... <other metadata> ...,
install_requires=[
'PyBoolNet # git+https://github.com/hklarner/PyBoolNet#2.3.0',
... <other packages> ...
]
)
Running pip install git+https://github.com/jcrozum/PyStableMotifs works perfectly, but I can't upload this to PyPI because of the following error from twine:
Invalid value for requires_dist. Error: Can't have direct dependency: 'PyBoolNet # git+https://github.com/hklarner/PyBoolNet#2.3.0'
My understanding is that direct links are forbidden by PyPI for security reasons. Nonetheless, PyBoolNet is a hard requirement for PyStableMotifs. What do I do? Give up on PyPI?
I just want pip install PyStableMotifs to work for my users. Ideally, this command should install the dependencies and I should not have to maintain two versions of setup.py.
Failing that, I have considered creating a "dummy" package on PyPI directing users to install using the command pip install git+https://github.com/jcrozum/PyStableMotifs. Is this a bad idea (or even possible)?
Are there already established best practices for this situation or other common workarounds?
EDIT:
For now, I have a clunky and totally unsatisfying workaround. I'm keeping two versions; a GitHub version that works perfectly, and a PyPI version that has the PyBoolNet requirement removed. If the user tries to import PyStableMotifs without PyBoolNet installed, an error message is shown that has install instructions for PyBoolNet. This is far from ideal in my mind, but it will have to do until I can find a better solution or until PyPI fixes this bug (or removes this feature, depending on who you ask).
My recommendation would be to get rid of the direct URL in install_requires, and tell your users where they can find that dependency PyBoolNet since it is not on PyPI. Don't force them on a specific installation method, but show them an example.
Maybe simply tell your users something like:
This project depends on PyBoolNet, which is not available on PyPI. One place where you can find it is at: https://github.com/hklarner/PyBoolNet.
One way to install PyStableMotifs as well as its dependency PyBoolNet is to run the following command:
python -m pip install 'git+https://github.com/hklarner/PyBoolNet#2.3.0#egg=PyBoolNet' PyStableMotifs
You could additionnally prepare a requirements.txt file and tell your users:
Install with the following command:
python -m pip install --requirement https://raw.githubusercontent.com/jcrozum/PyStableMotifs/master/requirements.txt
The content of requirements.txt could be something like:
git+https://github.com/hklarner/PyBoolNet#2.3.0#egg=PyBoolNet
PyStableMotifs
But in the end, you should really let your users choose how to install that dependency. Your project only need to declare that it depends on that library but not how to install it.
The installation instructions don't mention the need for Python or specific Python plugins. Although when I add coc.nvim to my vim plugs (Plug 'neoclide/coc.nvim', {'branch': 'release'}), install and restart Neovim, I get the following error:
[coc.nvim] Error on execute python script: request error nvim_command - Vim(pyxfile):E319: No "python3" provider found. Run ":checkhealth provider"
I'm a long time VIM/Neovim user and have my fair share of plugins installed, none of them has any dependency on 3rd party Python scripts, and I would like to keep it that way.
So my question is, does coc.nvim require Python or is there something misconfigured on my end?
You're using https://github.com/neoclide/coc-snippets , which will load and parse Ultisnips snippets, some snippets need Python to run.
You can disable Python by setting "snippets.ultisnips.usePythonx": false in your coc-settings.json.
I solved it using "snippets.ultisnips.usePythonx": false and running pip install neovim in my virtual environment.
I solved it by pip3 install --user pynvim
Hey so I've managed to get shapely.geometry to run just fine on PyCharm.
But the difficulty here is in getting the import to run on Jupyter notebook.
I have done:
import geopandas as gpd
This returns shapely.geometry doesn't exist.
I think I know how to fix this through downloading the file
"Shapely-1.6.4.post1-cp37-cp37m-win_amd64.whl" and doing conda install (that)... but it returned that the channel didnt exist...
So I did:
conda install --add channels https://www.lfd.uci.edu/~gohlke/pythonlibs/
(which is where I got the file from) which worked just fine so I then again did "conda install Shapely-1.6.4.post1-cp37-cp37m-win_amd64.whl" but it returned:
CondaHTTPError: HTTP 000 CONNECTION FAILED for url <https://www.lfd.uci.edu/~gohlke/pythonlibs/win-64/repodata.json>
A simple retry will get you on your way...
Tried that, didnt work. Someone please help. Reminder that I successfully installed shapely with all of its modules working through "pip install Shapely-1.6.4.post1-cp37-cp37m-win_amd64.whl" WITHIN Pycharm itself.
EDIT 1
Im following the textbook "Mastering Geospatial Anlsysis with Python" It got me to download the packages:
gdal
geos
shapely
fiona
pyshp
pyproj
rasterio
geopandas
EDIT 2
I dont know what i did but somehow i fixed it... but the thing is, i literally did nothing except take out a shapely file with a long name and kept the one just called "shapely".
If i have files like this
gdal-2.2.2-py36hcebd033_1
instead of this
gdal
Is that the problem?????? because if it is, then i dont know how to get files like that they just either appear or they dont.
Shapely is a wrapper of C++ library called GEOS that is not installed with the wheel. You should go to the page and install that library.
Or perhaps you have Pycharm for python 2 and Jupyter for python 3 (or vice-versa).
Running conda install -c conda-forge geos=3.7.1 worked for me.
I'm a RHEL newbie. I'm used to a non-Linux Unix, which has a fundamentally different way of dealing with packages.
I want to install ipython for a user on a vanilla RHEL7 system with yum as the package manager.
"yum install python" was fairly straightforward, but given that I'm new to the OS and I don't completely understand what ipython is, I am stumped as to how to proceed.
"yum install ipython" obviously doesn't work and every possible solution seems to require the installation of something else that I don't know how to install in a reasonable manner.
I am trying to keep things as generic as possible so it will be obvious how to update/remove software in the future, so anything that can be done with yum, would be probably preferable.
Installation instructions refer to pip, which I don't have. I possibly need setuptools to run pip, but I can't figure out the appropriate way to get that either. Maybe I can get one or either by installation the EPEL bundle of packages, but I can't find those for RHEL7, at least not in a way that doesn't seem like a "download and install this random file, trust us" method, which seems irresponsible.
Another option is anaconda. Again, there doesn't seem to be a yum-related way to install this, and anaconda itself is only a means to an end to download ipython, so that'd be two levels of abstraction away from the goal.
Additionally, do I even want "ipython" these days, or do I want "jupyter"?
All I care about is that the user should be able to type in "ipython" at the prompt and get the thing he is expecting.
Also, the python installed by yum is 2.7.5-48.el7, which does not seem to be current. I don't care about using the current version unless that prevents me from successfully installing ipython in some other manner, but I thought it might be relevant.
Any suggestions for how to install this thing is the most easily maintainable way? Do I not want the yum version of python?
Thanks for your patience.
Install python-pip from EPEL repository first ( https://fedoraproject.org/wiki/EPEL - it's compatible with all Red Hat entrprise Linux distros - be it CentOS, RHEL, Oracl, ScientificLinux or whatever), (or if you don't trust EPEL repo providers you can use get-pip.py ( https://bootstrap.pypa.io/get-pip.py ) script, but then you have to trust its providers instead) then install via
pip install ipython
I have a fresh Julia instalation on a machine that I want to use as a number-crunching server for various persons on a lab. There seems to be this nice package called jupyterhub wich makes the Jupyter Notebook interface avaible to various clients simultaneusly. A web page which I am unable to find again began suggesting something like "first install IJulia globally, then install JupyterHub..."
I cannot seem to find a nice way to install ONE package globally.
Update
In Julia-v0.7+, we need to use JULIA_DEPOT_PATH instead of JULIA_PKGDIR and the LOAD_PATH looks something like this:
julia> LOAD_PATH
3-element Array{Any,1}:
Base.CurrentEnv()
Any[Base.NamedEnv("v0.7.0"), Base.NamedEnv("v0.7"), Base.NamedEnv("v0"), Base.NamedEnv("default"), Base.NamedEnv("v0.7", create=true)]
"/Users/gnimuc/Codes/julia/usr/share/julia/stdlib/v0.7"
Old Post
"first install IJulia globally, then install JupyterHub..."
I don't know whether this is true or not, by following these steps below, you can install IJulia after you installed Jupyterhub.
Install packages system-wide/globally for every user
this question has already been answered here by Stefan Karpinski. so what we need is just use this method to install the IJulia.jl package.
There's a Julia variable called LOAD_PATH that is arranged to point at two system directories under your julia installation. E.g.:
julia> LOAD_PATH
2-element Array{Union(ASCIIString,UTF8String),1}:
"/opt/julia-0.3.3/usr/local/share/julia/site/v0.3"
"/opt/julia-0.3.3/usr/share/julia/site/v0.3"
If you install packages under either of those directories, then everyone using that Julia will see them. One way to do this is to run julia as a user who can write to those directories after doing export JULIA_PKGDIR=/opt/julia-0.3.3/usr/share/julia/site in the shell. That way Julia will use that as it's package directory and normal package commands will allow you to install packages for everyone....
Make IJulia working with Jupyterhub
in order to make IJulia and Jupyterhub working with each other for all the users, you should copy the folder your/user/.local/share/jupyter/kernels/julia/ to /usr/local/share/jupyter/kernels/. I write down some of the steps that I used in my test Dockerfile. the code is ugly, but it works.
Steps: (after you successfully installed Jupyterhub)
note that, you should do the following steps as root and I assume that your julia was globally installed at /opt/julia_0.4.0/.
make our global package directory and set up JULIA_PKGDIR:
mkdir /opt/global-packages
echo 'push!(LOAD_PATH, "/opt/global-packages/.julia/v0.4/")' >> /opt/julia_0.4.0/etc/julia/juliarc.jl
export JULIA_PKGDIR=/opt/global-packages/.julia/
install "IJulia" using package manager:
julia -e 'Pkg.init()'
julia -e 'Pkg.add("IJulia")'
copy kernelspecs to /usr/local/share/jupyter/kernels/ which can be used by any new user added by Jupyterhub:
jupyter kernelspec list
cd /usr/local/share/ && mkdir -p jupyter/kernels/
cp -r /home/your-user-name/.local/share/jupyter/kernels/julia-0.4-your-julia-version /usr/local/share/jupyter/kernels/