Develop Reference

Python packages are located in differente location

I am using Ubuntu 20.04 which comes python 3.8.
I installed python3.9 and made it as default python update-alternatives
under /usr/bin/ I have python2.7/ python3/ python3.8/ and python3.9/
==> Now the problem that I am facing is when I installed sqlalchemy using pip install sqlalchemy its version was 1.3.12, which has a compatibility problem with pandas because it requires version '1.4.0'.
>>>pip install --upgrade sqlalchemy
>>> Defaulting to user installation because normal site-packages is not writeable
Requirement already satisfied: sqlalchemy in /usr/lib/python3/dist-packages (1.3.12)
Collecting sqlalchemy
Downloading SQLAlchemy-1.4.31-cp38-cp38-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_17_x86_64.manylinux2014_x86_64.whl (1.6 MB)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1.6/1.6 MB 8.3 MB/s eta 0:00:00
Collecting greenlet!=0.4.17
Downloading greenlet-1.1.2-cp38-cp38-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (156 kB)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 156.6/156.6 KB 9.6 MB/s eta 0:00:00
Installing collected packages: greenlet, sqlalchemy
Successfully installed greenlet-1.1.2 sqlalchemy-1.4.31
I wrote the same command again it gave me this :
Defaulting to user installation because normal site-packages is not writeable
Requirement already satisfied: sqlalchemy in ./.local/lib/python3.8/site-packages (1.4.31)
Requirement already satisfied: greenlet!=0.4.17 in ./.local/lib/python3.8/site-packages (from sqlalchemy) (1.1.2)
I also did this to check:
>>>pip show sqlalchemy | grep Location
>>>Location: /home/Moe/.local/lib/python3.8/site-packages
but when I import sqlalchemy in a script it still uses the old version
it seems that the new version is installed in a different location
>>> print(sqlalchemy.__file__)
>>>/usr/lib/python3/dist-packages/sqlalchemy/__init__.py
Can Someone please explain this to me, and if possible explain the entire package management problem here

You are calling pip that is associated with your python 3.8, you can see that in the whl file that is downloaded:
Downloading SQLAlchemy-1.4.31-cp38-cp38-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_17_x86_64.manylinux2014_x86_64.whl
Note the cp38
And in the output of running the install again:
Requirement already satisfied: sqlalchemy in ./.local/lib/python3.8/site-packages (1.4.31)
Note the python3.8.
Since you have mentioned that you downloaded python 3.9, you are probably running your scripts using that version of python. You will need to use the pip that is associated with that python. If you are running your script with
python <scriptfile>
Then you should pip install with
python -m pip install ...

Librosa installation pip fail

I am trying to install librosa by pip install librosa on the mac terminal, pip3 also has the same problem. It also gets stuck when I try to install scikit-learn.
Doesn't go any further than:
Collecting librosa
Using cached librosa-0.8.1-py3-none-any.whl (203 kB)
Collecting packaging>=20.0
Using cached packaging-21.0-py3-none-any.whl (40 kB)
Requirement already satisfied: numpy>=1.15.0 in /opt/homebrew/lib/python3.9/site-packages (from librosa) (1.21.0)
Requirement already satisfied: scipy>=1.0.0 in /opt/homebrew/lib/python3.9/site-packages (from librosa) (1.7.0)
Collecting numba>=0.43.0
Using cached numba-0.53.1.tar.gz (2.2 MB)
Collecting resampy>=0.2.2
Using cached resampy-0.2.2.tar.gz (323 kB)
Requirement already satisfied: soundfile>=0.10.2 in /opt/homebrew/lib/python3.9/site-packages (from librosa) (0.10.3.post1)
Collecting scikit-learn!=0.19.0,>=0.14.0
Using cached scikit-learn-0.24.2.tar.gz (7.5 MB)
Installing build dependencies ... \
I am very new at this, please help I just want to draw some spectrograms.
python --version
Python 2.7.16
python3 --version
Python 3.9.6
pip --version
pip 21.1.3 from /opt/homebrew/lib/python3.9/site-packages/pip (python 3.9)

It might be useful for you to work in a virtual environment. If you are trying to install with python 3.9 there may be a number of dependency issues, so using a lower version may also solve your issues. However, do try to with a conda environment as this will allow you to more easily keep track of install packages etc. Here are the install instructions:
After the install you can create a conda environment with a lower python version:
conda create -n "py38" python=3.8 ipython
Activate the environment:
conda activate py38
Install librosa:
conda install -c conda-forge librosa

Error while trying to install PyQt designer on Macbook

I have installed PyQt5 on my Macbook, however when I try and run the command to install the tools, I am getting an error as follows:
ERROR: Could not find a version that satisfies the requirement pyqt5-plugins<5.15.2.3,>=5.15.2.2 (from pyqt5-tools) (from versions: none)
ERROR: No matching distribution found for pyqt5-plugins<5.15.2.3,>=5.15.2.2 (from pyqt5-tools)
Here is the full input and output:
(base) _-Air:Chess-Final _$ pip3.7 install pyqt5-tools
Collecting pyqt5-tools
Using cached pyqt5_tools-5.15.2.3.0.2-py3-none-any.whl (28 kB)
ERROR: Could not find a version that satisfies the requirement pyqt5-plugins<5.15.2.3,>=5.15.2.2 (from pyqt5-tools) (from versions: none)
ERROR: No matching distribution found for pyqt5-plugins<5.15.2.3,>=5.15.2.2 (from pyqt5-tools)
WARNING: You are using pip version 20.2.3; however, version 20.3.3 is available.
You should consider upgrading via the '/usr/local/bin/python3.7 -m pip install --upgrade pip' command.
I have tried downloading QT designer from its website, but since I want it for personal use, I am not able to get it (it requires company information)

So it turns out that pyqt5-tools is only available for Windows as seen on their site: https://pypi.org/project/pyqt5-tools/
Try an alternative such as QT-creator for Mac: https://www.qt.io/download
This post strongly supports using Homebrew: Python PyQt on macOS Sierra

Pip failing to install matplotlib

I had to redownload Python and PyCharm due to some issues with my old versions, and am now reinstalling some packages for my project. numpy and pandas installed fine using the PyCharm package manager interface, but when I try to install matplotlib I just get an error with message
ERROR: Command errored out with exit status 1:
When I look for more information, PyCharm suggests that I "Try to run pip install matplotlib from the system terminal. Make sure that you use the correct version of 'pip' installed for your Python interpreter located at [my path]". When I try to run the command in terminal, I get the following message:
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support pip 21.0 will remove support for this functionality.
Defaulting to user installation because normal site-packages is not writeable
Collecting matplotlib
Using cached matplotlib-2.2.5-cp27-cp27mu-manylinux1_x86_64.whl (12.8 MB)
Collecting python-dateutil>=2.1
Using cached python_dateutil-2.8.1-py2.py3-none-any.whl (227 kB)
Collecting kiwisolver>=1.0.1
Using cached kiwisolver-1.1.0-cp27-cp27mu-manylinux1_x86_64.whl (93 kB)
Collecting numpy>=1.7.1
Using cached numpy-1.16.6-cp27-cp27mu-manylinux1_x86_64.whl (17.0 MB)
Collecting six>=1.10
Using cached six-1.15.0-py2.py3-none-any.whl (10 kB)
Collecting cycler>=0.10
Using cached cycler-0.10.0-py2.py3-none-any.whl (6.5 kB)
Collecting pyparsing!=2.0.4,!=2.1.2,!=2.1.6,>=2.0.1
Using cached pyparsing-2.4.7-py2.py3-none-any.whl (67 kB)
Collecting pytz
Using cached pytz-2020.4-py2.py3-none-any.whl (509 kB)
Collecting backports.functools-lru-cache
Using cached backports.functools_lru_cache-1.6.1-py2.py3-none-any.whl (5.7 kB)
Collecting subprocess32
Using cached subprocess32-3.5.4-cp27-cp27mu-manylinux2014_x86_64.whl (69 kB)
Requirement already satisfied: setuptools in /home/[myusername]/.local/lib/python2.7/site-packages (from kiwisolver>=1.0.1->matplotlib) (44.1.1)
Installing collected packages: six, python-dateutil, kiwisolver, numpy, cycler, pyparsing, pytz, backports.functools-lru-cache, subprocess32, matplotlib
Successfully installed backports.functools-lru-cache-1.6.1 cycler-0.10.0 kiwisolver-1.1.0 matplotlib-2.2.5 numpy-1.16.6 pyparsing-2.4.7 python-dateutil-2.8.1 pytz-2020.4 six-1.15.0 subprocess32-3.5.4
I'm using windows, but have Ubuntu installed, which I used to try to run that command, since when I try to do anything with pip on git bash I get bash: /c/Users/[myusername]/AppData/Local/Microsoft/WindowsApps/python: Permission denied.
Anyways, I suppose the problem is that I have Python 2.7 installed (python --version agrees), which won't cooperate with matplotlib. So, I go to /home/[myusername]/.local/lib/python2.7/site-packages using Ubuntu terminal and use rm -r python2.7 to delete folder. Since I have Python 3.9 installed at C:\Users\[myusername]\AppData\Local\Programs\Python\Python39\python.exe I assumed that this would just default to the newer version. However, when I restart everything, Python 2.7 just appears again in its old location, and that version continues to run. I believe this has something to do with how I'm using Ubuntu, since Python 2.7 exists only outside my C: drive. But, I'm not sure how to go from here to install matplotlib. Would appreciate any help!

Install Mayavi for Python 3.7.1 in Windows 10

Under Windows 10, I'm trying to run a Python script which contains the line
from mayavi import mlab
Therefore I'm trying to install Mayavi by running
pip install mayavi
from the Windows PowerShell. I then get
Collecting mayavi
Using cached https://files.pythonhosted.org/packages/83/9e/293ba57353ed258c2f64d54bf00ca1447c1f38f4eb60d0e762ddec57bf51/mayavi-4.6.2.tar.bz2
Collecting apptools (from mayavi)
Using cached https://files.pythonhosted.org/packages/78/84/64764e2c87fcb7ad7521bdabc7c44c109b80691f94218cbddd5df2ee682c/apptools-4.4.0.tar.bz2
Collecting envisage (from mayavi)
Using cached https://files.pythonhosted.org/packages/ea/2a/7efcd2c44a638a5e3e65e39f7e5bd4cf952ef4ffc71768730cf19fef1e4e/envisage-4.7.0-py3-none-any.whl
Requirement already satisfied: numpy in c:\users\adria\appdata\local\programs\python\python37-32\lib\site-packages (from mayavi) (1.15.4)
Collecting pyface>=6.0.0 (from mayavi)
Using cached https://files.pythonhosted.org/packages/45/fe/7150742f7053cb5082f15704c064a5c683f42dfc00411ce173287651e33a/pyface-6.0.0.tar.gz
Collecting pygments (from mayavi)
Using cached https://files.pythonhosted.org/packages/13/e5/6d710c9cf96c31ac82657bcfb441df328b22df8564d58d0c4cd62612674c/Pygments-2.3.1-py2.py3-none-any.whl
Collecting traits>=4.6.0 (from mayavi)
Using cached https://files.pythonhosted.org/packages/56/47/03f50e82e1ff1e8a602c5f2cf12f08675f79a7169629fe4ce521e59d265f/traits-4.6.0.tar.bz2
Collecting traitsui>=6.0.0 (from mayavi)
Using cached https://files.pythonhosted.org/packages/f2/06/3ad35a78e1ca82d762e2d9ffe9ed6c9dd405caa340066052d7ec186b9b1b/traitsui-6.0.0.tar.gz
Collecting vtk (from mayavi)
Could not find a version that satisfies the requirement vtk (from mayavi) (from versions: )
No matching distribution found for vtk (from mayavi)
Running pip install vtk gives
Collecting vtk
Could not find a version that satisfies the requirement vtk (from versions: )
No matching distribution found for vtk
I installed VTK manually with https://www.vtk.org/files/release/7.1/vtkpython-7.1.1-Windows-64bit.exe but it does not solve the problem.
Running python --version returns Python 3.7.1 and running pip --version or pip3 --version returns pip 18.1 from c:\users\adria\appdata\local\programs\python\python37-32\lib\site-packages\pip (python 3.7).
How do I solve this problem?

Go to anaconda cloud then search mayavi then, in the python console, tape
conda install -c conda-forge mayavi
Perhaps before you have to install VTK module with
conda install -c conda-forge vtk
Then restart the console, and enjoy!