Develop Reference

unable to install requirements txt

I am getting below mentioned error when i am trying to install dependencies
,
./psycopg/psycopg.h:35:10: fatal error: libpq-fe.h: No such file or
directory
35 | #include <libpq-fe.h>
Depends: libpq5 (= 12.9-0ubuntu0.20.04.1) but 14.1-2.pgdg20.04+1 is
to be installed

This error comes from the fact that you do not have the libpq-dev package installed on your Ubuntu system.
You can solve this by either installing that package, or by using the psycopg2-binary package from pip instead of the psycopg2 package. The psycopg2-binary package contains a pre-compiled binary which means that you don't have to build the C extension when installing the dependencies of your app.
So, plan of action:
Either, you make sure to install the dependent packages on Ubuntu according to the psycopg2 documentation:
sudo apt install python3-dev libpq-dev
And then you should be able to run your requirements using pip install -r requirements.txt.
The other option is to change the psycopg2 line in your requirements.txt file so that it says psycopg2-binary instead, and then you shouldn't have to install the libpq-dev package.
You can read more about the differences between psycopg2 and psycopg2-binary in their slightly longer installation documentation

For specific version of python try
sudo apt install python-dev libpq-dev
For example
sudo apt install python3.9-dev libpq-dev
For python version 3.9

I'm trying to download pygame but it keeps coming up with the same error (error: command 'gcc' failed with exit status 1)? [duplicate]

I wanted to install eventlet on my system in order to have "Herd" for software deployment.. but the terminal is showing a gcc error:
root#agrover-OptiPlex-780:~# easy_install -U eventlet
Searching for eventlet
Reading http://pypi.python.org/simple/eventlet/
Reading http://wiki.secondlife.com/wiki/Eventlet
Reading http://eventlet.net
Best match: eventlet 0.9.16
Processing eventlet-0.9.16-py2.7.egg
eventlet 0.9.16 is already the active version in easy-install.pth
Using /usr/local/lib/python2.7/dist-packages/eventlet-0.9.16-py2.7.egg
Processing dependencies for eventlet
Searching for greenlet>=0.3
Reading http://pypi.python.org/simple/greenlet/
Reading https://github.com/python-greenlet/greenlet
Reading http://bitbucket.org/ambroff/greenlet
Best match: greenlet 0.3.4
Downloading http://pypi.python.org/packages/source/g/greenlet/greenlet- 0.3.4.zip#md5=530a69acebbb0d66eb5abd83523d8272
Processing greenlet-0.3.4.zip
Writing /tmp/easy_install-_aeHYm/greenlet-0.3.4/setup.cfg
Running greenlet-0.3.4/setup.py -q bdist_egg --dist-dir /tmp/easy_install-_aeHYm/greenlet-0.3.4/egg-dist-tmp-t9_gbW
In file included from greenlet.c:5:0:
greenlet.h:8:20: fatal error: Python.h: No such file or directory
compilation terminated.
error: Setup script exited with error: command 'gcc' failed with exit status 1`
Why can't Python.h be found?

Your install is failing because you don't have the python development headers installed. You can do this through apt on ubuntu/debian with:
sudo apt-get install python-dev
for python3 use:
sudo apt-get install python3-dev
For eventlet you might also need the libevent libraries installed so if you get an error talking about that you can install libevent with:
sudo apt-get install libevent-dev

For Fedora:
sudo yum install python-devel
sudo yum install libevent-devel
and finally:
sudo easy_install gevent

What worked for me on CentOS was:
sudo yum -y install gcc
sudo yum install python-devel

For Redhat Versions(Centos 7) Use the below command to install Python Development Package
Python 2.7
sudo yum install python-dev
Python 3.4
sudo yum install python34-devel
Python 3.6
sudo yum install python36-devel
If the issue is still not resolved then try installing the below packages -
sudo yum install python-devel
sudo yum install openssl-devel
sudo yum install libffi-devel

On MacOS I had trouble installing fbprophet which requires pystan which requires gcc to compile. I would consistently get the same error: command 'gcc' failed with exit status 1
I think I fixed the problem for myself thus:
I used brew install gcc to install the newest version, which ended up being gcc-8
Then I made sure that when gcc ran it would use gcc-8 instead.
It either worked because I added alias gcc='gcc-8 in my .zshrc (same as .bashrc but for zsh), or because I ran export PATH=/usr/local/bin:$PATH (see comment)
Also: all my attempts were inside a virtual environment and I only succeeded by installing fbprophet globally (with pip), but still no success inside a venv

This is an old post but I just run to the same problem on AWS EC2 installing regex. This working perfectly for me
sudo yum -y install gcc
and next
sudo yum -y install gcc-c++

If it is still not working, you can try this
sudo apt-get install build-essential
in my case, it solved the problem.

try this :
sudo apt-get install libblas-dev libatlas-base-dev
I had a similar issue on Ubuntu 14.04. For me the following Ubuntu packages

On MacOS I also had problems trying to install fbprophet which had gcc as one of its dependencies.
After trying several steps as recommended by #Boris the command below from the Facebook Prophet project page worked for me in the end.
conda install -c conda-forge fbprophet
It installed all the needed dependencies for fbprophet. Make sure you have anaconda installed.

This page is gonna save your life, for all further lib issues that are forthcoming,
For Alpine(>=3.6), use
apk --update --upgrade add gcc musl-dev jpeg-dev zlib-dev libffi-dev cairo-dev pango-dev gdk-pixbuf-dev

For CentOS 7.2：
LSB Version: :core-4.1-amd64:core-4.1-noarch
Distributor ID: CentOS
Description: CentOS Linux release 7.2.1511 (Core)
Release: 7.2.1511
Codename: Core
Install eventlet:
sudo yum install python-devel
sudo easy_install -ZU eventlet
Terminal info：
[root#localhost ~]# easy_install -ZU eventlet
Searching for eventlet
Reading http://pypi.python.org/simple/eventlet/
Best match: eventlet 0.19.0
Downloading https://pypi.python.org/packages/5a/e8/ac80f330a80c18113df0f4f872fb741974ad2179f8c2a5e3e45f40214cef/eventlet-0.19.0.tar.gz#md5=fde857181347d5b7b921541367a99204
Processing eventlet-0.19.0.tar.gz
Running eventlet-0.19.0/setup.py -q bdist_egg --dist-dir /tmp/easy_install-Hh9GQY/eventlet-0.19.0/egg-dist-tmp-rBFoAx
Adding eventlet 0.19.0 to easy-install.pth file
Installed /usr/lib/python2.6/site-packages/eventlet-0.19.0-py2.6.egg
Processing dependencies for eventlet
Finished processing dependencies for eventlet

For openSUSE 42.1 Leap Linux use this
sudo zypper install python3-devel

I am using MacOS catalina 10.15.4. None of the posted solutions worked for me. What worked for me is:
>> xcode-select --install
xcode-select: error: command line tools are already installed, use "Software Update" to install updates
>> env LDFLAGS="-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib" pip install psycopg2==2.8.4
Collecting psycopg2==2.8.4
Using cached psycopg2-2.8.4.tar.gz (377 kB)
Installing collected packages: psycopg2
Attempting uninstall: psycopg2
Found existing installation: psycopg2 2.7.7
Uninstalling psycopg2-2.7.7:
Successfully uninstalled psycopg2-2.7.7
Running setup.py install for psycopg2 ... done
Successfully installed psycopg2-2.8.4
use pip3 for python3

if you are on Mac as myself, try this in your terminal: xcode-select --install
Then accept the installation request, and it works afterwards as described in this issue

Build from source and install, this is fixed in the latest release (10.3+):
mkdir -p /tmp/install/netifaces/
cd /tmp/install/netifaces && wget -O "netifaces-0.10.4.tar.gz" "https://pypi.python.org/packages/source/n/netifaces/netifaces-0.10.4.tar.gz#md5=36da76e2cfadd24cc7510c2c0012eb1e"
tar xvzf netifaces-0.10.4.tar.gz
cd netifaces-0.10.4 && python setup.py install

Similarly I fixed it like this (notice python34):
sudo yum install python34-devel

sudo apt install gcc
It works for PyCharm on Ubuntu 20.10.

If you are migrating to a more modern version of python3 e.g. python3.5 to python3.8 You may want to check/upgrade the versions of the library that are failing if you have already installed the recommended libraries to handle gcc building python3-dev + other libraries as suggested.
It depends on the package. Some versions of the packages may not be supported on later versions of python3.

Python failed building wheel for dlib Ubuntu

I am attempting to install dlib to my python virtual environment.
There is a very similar problem here and I followed the exact steps to no avail.
Somehow I am able to import dlib when running code and I managed to do that by git cloning git clone -b pybind11 https://github.com/supervacuus/dlib.git.
But when I attempt to install it pip3 install dlib or a library that depends on it such as pip3 install face_recognition I get errors stating that ERROR: Failed building wheel for dlib
Full execution logs and error here https://gist.github.com/GhettoBurger996/1e6a423b88b7435c8759255e19fa5e60
I am using 3.5.2 and Ubuntu 16.04

Question is a bit old but I ran into a similar problem where installing dlib using pip3 would fail.
Installing the following dependencies fixed it for me:
$ sudo apt-get install build-essential cmake
$ sudo apt-get install libgtk-3-dev
$ sudo apt-get install libboost-all-dev
From the posted error logs it seems that you had cmake installed already so the first line might not be necessary for you.

Install numpy in Python virtualenv

I've created virtualenv for Python 2.7.4 on Ubuntu 13.04. I've installed python-dev.
I have the error when installing numpy in the virtualenv.
Maybe, you have any ideas to fix?

The problem is SystemError: Cannot compile 'Python.h'. Perhaps you need to install python-dev|python-devel.
so do the following in order to obtain 'Python.h'
make sure apt-get and gcc are up to date
sudo apt-get update
sudo apt-get upgrade gcc
then install the python2.7-dev
sudo apt-get install python2.7-dev
and I see that you have most probably already done the above things.
pip will eventually spit out another error for not being able to write into /user/bin/blahBlah/dist-packages/ or something like that because it couldn't figure out that it was supposed to install your desiredPackage (e.g. numpy) within the active env (the env created by virtualenv which you might have even changed directory to while doing all this)
so do this:
pip -E /some/path/env install desiredPackage
that should get the job done... hopefully :)
---Edit---
From PIP Version 1.1 onward, the command pip -E doesn't work. The following is an excerpt from the release notes of version 1.1 (https://pip.pypa.io/en/latest/news.html)
Removed -E/--environment option and PIP_RESPECT_VIRTUALENV; both use a restart-in-venv mechanism that's broken, and neither one is useful since every virtualenv now has pip inside it. Replace pip -E path/to/venv install Foo with virtualenv path/to/venv && path/to/venv/pip install Foo

If you're on Python3 you'll need to do sudo apt-get install python3-dev. Took me a little while to figure it out.

If you're hitting this issue even though you've installed all OS dependencies (python-devel, fortran compiler, etc), the issue might be instead related to the following bug:
"numpy installation thru install_requires directive issue..."
Work around is to manually install numpy in your (virtual) environment before running setup.py to install whatever you want to install that depends on numpy.
eg, pip install numpy then python ./setup.py install

This answer is for those of us that compiled python from source or installed it to a non standard directory. In my case, python2.7 was installed to /usr/local and the include files were installed to /usr/local/include/python2.7
C_INCLUDE_PATH=/usr/local/include/python2.7:$C_INCLUDE_PATH pip install numpy

I recently had the same problem. I run Debian Jessie and tried to install numpy from a Python 2.7.9 virtualenv. I got the same error -- numpy complaining that Python.h is missing while python2.7-dev and gcc are already installed.
File "numpy/core/setup.py", line 42, in check_types
],
File "numpy/core/setup.py", line 293, in check_types
SystemError: Cannot compile 'Python.h'. Perhaps you need to install python-dev|python-devel.
I'm running pip 1.5.6 and it doesn't appear to have command line option '-E'
$ pip -V
pip 1.5.6 from /home/alex/.virtualenvs/myenv/local/lib/python2.7/site- packages (python 2.7)
Upgrading pip to the latest verson 7.0.3 solves the problem
$ pip install --upgrade pip
Downloading/unpacking pip from https://pypi.python.org/packages/py2.py3/p/pip/pip-7.0.3-py2.py3-none-any.whl#md5=6950e1d775fea7ea50af690f72589dbd
Downloading pip-7.0.3-py2.py3-none-any.whl (1.1MB): 1.1MB downloaded
Installing collected packages: pip
Found existing installation: pip 1.5.6
Uninstalling pip:
Successfully uninstalled pip
Successfully installed pip
Cleaning up...
Now it is possible to install numpy
$ pip install numpy
Collecting numpy
Downloading numpy-1.9.2.tar.gz (4.0MB)
100% |████████████████████████████████| 4.0MB 61kB/s
Installing collected packages: numpy
Running setup.py install for numpy
Successfully installed numpy-1.9.2

This is probably because you do not have the python-dev package installed. You can install it like this:
sudo apt-get install python-dev
You can also install it via the Software Center:

#samkhan13 solution didn't work for me as pip said it doesn't have the -E option.
I was still getting the same error, but what worked for me was to install matplotlib, which installed numpy.

Installing SciPy with pip

It is possible to install NumPy with pip using pip install numpy.
Is there a similar possibility with SciPy? (Doing pip install scipy does not work.)
Update
The package SciPy is now available to be installed with pip!

Prerequisite:
sudo apt-get install build-essential gfortran libatlas-base-dev python-pip python-dev
sudo pip install --upgrade pip
Actual packages:
sudo pip install numpy
sudo pip install scipy
Optional packages:
sudo pip install matplotlib OR sudo apt-get install python-matplotlib
sudo pip install -U scikit-learn
sudo pip install pandas
src

An attempt to easy_install indicates a problem with their listing in the Python Package Index, which pip searches.
easy_install scipy
Searching for scipy
Reading http://pypi.python.org/simple/scipy/
Reading http://www.scipy.org
Reading http://sourceforge.net/project/showfiles.php?group_id=27747&package_id=19531
Reading http://new.scipy.org/Wiki/Download
All is not lost, however; pip can install from Subversion (SVN), Git, Mercurial, and Bazaar repositories. SciPy uses SVN:
pip install svn+http://svn.scipy.org/svn/scipy/trunk/#egg=scipy
Update (12-2012):
pip install git+https://github.com/scipy/scipy.git
Since NumPy is a dependency, it should be installed as well.

In Ubuntu 10.04 (Lucid), I could successfully pip install scipy (within a virtualenv) after installing some of its dependencies, in particular:
$ sudo apt-get install libamd2.2.0 libblas3gf libc6 libgcc1 libgfortran3 liblapack3gf libumfpack5.4.0 libstdc++6 build-essential gfortran libatlas-sse2-dev python-all-dev

To install scipy on windows follow these instructions:-
Step-1 : Press this link http://www.lfd.uci.edu/~gohlke/pythonlibs/#scipy to download a scipy .whl file (e.g. scipy-0.17.0-cp34-none-win_amd64.whl).
Step-2: Go to the directory where that download file is there from the command prompt (cd folder-name ).
Step-3: Run this command:
pip install scipy-0.17.0-cp27-none-win_amd64.whl

I tried all the above and nothing worked for me. This solved all my problems:
pip install -U numpy
pip install -U scipy
Note that the -U option to pip install requests that the package be upgraded. Without it, if the package is already installed pip will inform you of this and exit without doing anything.

If I first install BLAS, LAPACK and GCC Fortran as system packages (I'm using Arch Linux), I can get SciPy installed with:
pip install scipy

On Fedora, this works:
sudo yum install -y python-pip
sudo yum install -y lapack lapack-devel blas blas-devel
sudo yum install -y blas-static lapack-static
sudo pip install numpy
sudo pip install scipy
If you get any public key errors while downloading, add --nogpgcheck as parameter to yum, for example:
yum --nogpgcheck install blas-devel
On Fedora 23 onwards, use dnf instead of yum.

For the Arch Linux users:
pip install --user scipy prerequisites the following Arch packages to be installed:
gcc-fortran
blas
lapack

Addon for Ubuntu (Ubuntu 10.04 LTS (Lucid Lynx)):
The repository moved, but a
pip install -e git+http://github.com/scipy/scipy/#egg=scipy
failed for me... With the following steps, it finally worked out (as root in a virtual environment, where python3 is a link to Python 3.2.2):
install the Ubuntu dependencies (see elaichi), clone NumPy and SciPy:
git clone git://github.com/scipy/scipy.git scipy
git clone git://github.com/numpy/numpy.git numpy
Build NumPy (within the numpy folder):
python3 setup.py build --fcompiler=gnu95
Install SciPy (within the scipy folder):
python3 setup.py install

In my case, it wasn't working until I also installed the following package : libatlas-base-dev, gfortran
sudo apt-get install libatlas-base-dev gfortran
Then run pip install scipy

install python-3.4.4
scipy-0.15.1-win32-superpack-python3.4
apply the following commend doc
py -m pip install --upgrade pip
py -m pip install numpy
py -m pip install matplotlib
py -m pip install scipy
py -m pip install scikit-learn

The answer is yes, there is.
First you can easily install numpy use commands:
pip install numpy
Then you should install mkl, which is required by Scipy, and you can download it here
After download the file_name.whl you install it
C:\Users\****\Desktop\a> pip install mkl_service-1.1.2-cp35-cp35m-win32.whl
Processing c:\users\****\desktop\a\mkl_service-1.1.2-cp35-cp35m-win32.whl
Installing collected packages: mkl-service
Successfully installed mkl-service-1.1.2
Then at the same website you can download scipy-0.18.1-cp35-cp35m-win32.whl
Note:You should download the file_name.whl according to you python version, if you python version is 32bit python3.5 you should download this one, and the "win32" is about your python version, not your operating system version.
Then install file_name.whl like this:
C:\Users\****\Desktop\a>pip install scipy-0.18.1-cp35-cp35m-win32.whl
Processing c:\users\****\desktop\a\scipy-0.18.1-cp35-cp35m-win32.whl
Installing collected packages: scipy
Successfully installed scipy-0.18.1
Then there is only one more thing to do: comment out a specfic line or there will be error messages when you imput command "import scipy".
So comment out this line
from numpy._distributor_init import NUMPY_MKL # requires numpy+mkl
in this file: your_own_path\lib\site-packages\scipy__init__.py
Then you can use SciPy :)
Here tells you more about the last step.
Here is a similar anwser to a similar question.

Besides all of these answers,
If you install python of 32bit on your 64bit machine, you have to download scipy of 32-bit irrespective of your machine.
http://www.lfd.uci.edu/~gohlke/pythonlibs/
In the above URL you can download the packages and command is: pip install

For gentoo, it's in the main repository:
emerge --ask scipy

You can also use this in windows with python 3.6 python -m pip install scipy