We Keep Coding

How to fix the error that I receive when installing numpy in Python?

I have installed Python 3.10.6 and Pycharm community edition.
Everything was working until I tried to use numpy.
pip3 install numpy
import numpy as np
This is the error message:
pip3 install numpy
^^^^^^^
SyntaxError: invalid syntax
I also have tried to use pip install numpy and pip2 install numpy and pip3 install numpy scipy, but same error. Reinstalling both python and pycharm didn't help.

Ah, I understand your problem more specifically now. I also use PyCharm, and this same problem happened to me. It was very frustrating, and took me lots of reading to fix it.
PyCharm and other IDEs (integrated development environment) have something called 'run configurations' attached to each file you are working on. These run configurations basically specify which directory on the hard drive the file will use to read and execute your commands. The directory will contain the libraries you need to run your code.
They use these configurations to make it easy to quickly choose which directory (and which libraries) you want a certain file to use. You must specify these configurations in PyCharm for your specific file to run using Numpy. The great thing about PyCharm is that you can actually specify libraries you want to use within the IDE itself (and bypass having to specify a computer-native directory).
Here's How
Go to PyCharm Preferences
Expand the arrow that says 'Project: (your project name)'
Click on 'Python Interpreter'
Click the small '+' symbol
Type in 'numpy' to search for the library (package)
Click install package
Now try to run your file and it should be good to go!
Note that you must do this for each package you wish to use when accessing your file, and as you advance your programming knowledge it will be necessary to learn how to specify the directory you want PyCharm to run the Python Interpreter from. Since you are only using one library though, I think this solution should be fine for the time being.

You should install numpy with that command in your bash/zsh shell.
pip3 install numpy
the python script can then import it.
to test, run pip3 install numpy
then,
python to open a python shell.
and then you'll see
>>>
Type import numpy as np and be sure it imports. It should now.

It can be maddeningly confusing when first starting out with python and trying to figure out how to download libraries. Here are a few critical things I wish I understood before starting my Python journey, as well as the answer to your question.
Python is the language, and the files that support its functionality are located on the hard drive.
Libraries (like Numpy) can be thought of almost as interpreters (note that we are not using the computer definition of 'interpreter') and are stored alongside the Python files on the hard drive. They give Python more flexibility in terms of what it is able to do by increasing what commands Python is able to understand.
Once a library is downloaded, it must be imported to your Python script before you start writing library-specific commands. Importing a library tells Python: "Hey, I'm going to be writing some commands that you haven't seen before, but here is the library with the commands and what they want you to do in a way that you understand."
'pip' is Python's installer for these libraries.
Ex) I have a csv file that I want to read. I learn that Pandas has a csv reader function:
pandas.read_csv()
If I were to type this function in a script, Python would have no idea what I meant. But if I were to download Pandas, then import it into my script, Python would understand exactly what I'm saying.
How to Download Numpy
Assuming you are on Windows, open the terminal (command prompt) and run the command:
py -m pip install numpy
If you don't already have it, the terminal should have a few lines run and should end with something like 'numpy installed successfully'.
You can check to see if you have it by running the following command in your terminal:
py -m pip list
This command provides you with a list of all the downloaded libraries. You can check among them to make sure Numpy is downloaded.
Importing Libraries
Once you've downloaded the libraries you need, you need to import them into your script (the Python file where you are writing your code) in order for it to run properly. This is accomplished using the import command. One important thing to note is that you can import libraries and assign them a nickname using the as modifier.
Ex) Back to that csv file I want to read. I don't want to type 'pandas' in front of all the Pandas commands, so when I import it into the script I abbreviate it as 'pd':
import pandas as pd
pd.read_csv()
See the difference?
TL;DR for Your Scenario
Go to the terminal, and use the py -m pip list command to check if you have Numpy downloaded. If not, run the py -m pip install numpy command. Then go to your script with your actual python code, and import numpy with the import numpy command. Common Python practice is to import numpy as np, FYI.
Hope this clears things up.
It may say that you need to upgrade pip, which is fine, and it should give you a command to run that will upgrade pip to the newest version.

Trying to import GitHub module

I'm trying to import https://github.com/chrisconlan/algorithmic-trading-with-python in my code. I've never imported anything from GitHub before and have looked at various other questions that have been asked on Stack Overflow regarding this problem but it just doesn't work. When I try to run the 'portfolio.py' code for example I keep getting a ModuleNotFound error for 'pypm'. What exactly is the correct way to import such a module or the whole GitHub directory?
I'm working with Visual Studio Code on Windows.

You will need to pip install the module. In your case the command you would need to run is python -m pip install -U git+https://github.com/chrisconlan/algorithmic-trading-with-python. Once you have done that you need to find the name of the module. You can do this with pip list. Find the name of the module you just installed.
Then you just stick import <module name> at the top of your code with the rest of your imports.

What i used to do in this is to clone the repository on the folder where are installed the python's packages. This is useful when you do not want to use the pip cmd tool, keeping the pip's cache memory under control.

Python Libraries - Making them work on PCs that arent mine

Apologies if this is a very stupid question but I am new to python and although I have done some googling I cannot think how to phrase my search query.
I am writing a python script that relies on some libraries (pandas, numpy and others). At some point in the future I will be passing this script onto my University so they can mark it etc. I am fairly confident that the lecturer will have python installed on their PC but I cannot be sure they will have the relevant libraries.
I have included a comments section at the top of the script outlining the install instructions for each library but is there a better way of doing this so I can be sure the script will work regardless of what libraries they have?
An example of my script header
############### - Instructions on how to import libraries - ###############
#using pip install openpyxl using the command - pip install openpyxl
#########################################################################
import openpyxl
import random
import datetime

Distributing code is a huge chapter where you can invest enormous amounts of time in order to get things right, according to the current best practices and what not. I think there is different degrees of rightness to solutions to your problem, with more rightness meaning more work. So you have to pick the degree you are comfortable with and are good to go.
The best route
Python supports packaging, and the safest way to distribute code is to package it. This allows you to specify requirements in a way that installing your code will automatically install all dependencies as well.
You can use existing cookiecutters, which are project-templates, to create the base you need to build packages:
pip install cookiecutter
cookiecutter https://github.com/audreyr/cookiecutter-pypackage
Running this, and answering the ensuing questions, will leave you with python code that can be packaged. You can add the packages you need to the setup.py file:
requirements = ['openpyxl']
Then you add your script under the source directory and build the package with:
pip wheel .
Let's say you called your project my_script, you got yourself a fresh my_script-0.1.0-py2.py3-none-any.wheel file that you can send to your lecturer. When they install it with pip, openpyxl will be automatically installed in case it isn't already.
Unfortunately, if they should also be able to execute your code you are not done yet. You need to add a __main__.py file to the my_script folder before packaging it, in which you import and execute the parts of your code that are runnable:
my_script/my_script/__main__.py:
from . import runnable_script
if __name__ == '__main__':
runnable_script.run()
The installed package can then be run as a module with python -m my_script
The next best route
If you really only have a single file and want to communicate to your lecturer which requirements are needed to run the script, send them both your script and a file called requirements.txt, which contains the following lines:
openpyxl
.. and that's it. If there are other requirements, put them on separate lines. If the lecturer has spent any amount of time working with python, they should know that running pip install -r requirements.txt will install the requirements needed to run the code you have submitted.
The if-you-really-have-to route
If all your lecturer knows how to do is entering python and then the name of your script, use DudeCoders approach. But be aware that silently installing requirements without even interactive prompts to the user is a huge no-no in the software-engineering world. If you plan to work in programming you should start with good practices rather sooner than later.

You can firstly make sure that the respective library is installed or not by using try | except, like so:
try:
import numpy
except ImportError:
print('Numpy is not installed, install now to continue')
exit()
Now, if numpy is installed in his computer, then system will just import numpy and will move on, but if Numpy is not installed, then the system will exit python logging the information required, i.e., x is not installed.
And implement the exact same for each and every library you are using.
But if you want to directly install the library which is not installed, you can use this:
Note: Installing libraries silently is not a recommended way.
import os
try:
import numpy
except ImportError:
print('Numpy is not installed, installing now......')
resultCode = os.system('pip install numpy')
if resultCode == 0:
print('Numpy installed!')
import numpy
else:
print('Error occured while installing numpy')
exit()
Here, if numpy is already installed, then the system will simply move on after installing that, but if that is not installed, then the system will firstly install that and then will import that.

How can you import a local version of a python package?

I think I've found a bug in matplotlib. I'm using anaconda as a package manager, but had to download matplotlib from github in order to edit it.
How do I import my modified version of matplotlib in order to test it? I tried using
import /absolute/path/to/modified/matplotlib
, but that didn't work. Ideally I would like to create a conda environment that uses the modified matplotlib instead of the original, so I can easily switch between the two.
How do you test and run a modified version of an open source library, without messing up your original version of the package? Is there a way to import a library from an absolute path?

Try this
import sys
sys.path.append('/absolute/path/to/modified/matplotlib')
import matplotlib # modified

Another option not mentioned, if you just put the matplotlib module (copy or move) in the directory of your project, python will check there first, find the version you put there, and look no further. This is exactly the reason why you shouldn't name your files, for example, math.py.

You can install a local version by telling anaconda to install the tar-ball of the package directly, i.e.
conda install package-version-py27.tar.bz2
You might also be able to use the --use-local argument.
See: https://github.com/conda/conda/issues/5266, https://github.com/conda/conda/issues/1884

How to install a package using the python-apt API

I'm quite a newbie when it comes to Python, thus I beg foregiveness beforehand :). That said, I'm trying to make a script that, among other things, installs some Linux packages. First I tried to use subopen as explained here. While this can eventually work, I stumbled upon the python-apt API and since I'm not a big fan or re-inventing the wheel, I decided to give a try.
Problem comes when trying to find examples/tutorials on installing a package using python-apt. Searching the documentation I found the PackageManager class that has some methods to install a package. I tried some simple code to get this working:
apt_pkg.PackageManager.install("python")
This does not seem to work that easily, the install method expects apt_pkg.PackageManager instead of a plain String. Thus, looking a bit more, I found this example that looks promising, but I'm a bit reluctant to use since I don't really understand some of what is happening there.
Then, has anyone tried to install a package using python-apt or should I go for using plain-old subopen style?
Thanks!

It's recommended to use the apt module from the python-apt Debian package. This is a higher level wrapper around the underlying C/C++ libapt-xxx libraries and has a Pythonic interface.
Here's an example script which will install the libjs-yui-doc package:
#!/usr/bin/env python
# aptinstall.py
import apt
import sys
pkg_name = "libjs-yui-doc"
cache = apt.cache.Cache()
cache.update()
cache.open()
pkg = cache[pkg_name]
if pkg.is_installed:
print "{pkg_name} already installed".format(pkg_name=pkg_name)
else:
pkg.mark_install()
try:
cache.commit()
except Exception, arg:
print >> sys.stderr, "Sorry, package installation failed [{err}]".format(err=str(arg))
As with the use of apt-get, this must be run with superuser privileges to access and modify the APT cache.
$ sudo ./aptinstall.py
If you're attempting a package install as part of a larger script, it's probably a good idea to only raise to root privileges for the minimal time required.
You can find a small example in the /usr/share/pyshared/apt/progress/gtk2.py:_test() function showing how to install a package using a GTK front-end.