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ElasticBeanstalk PHP with Python - Install packages with pip [duplicate]

I want to install pip. It should support Python 3, but it requires setuptools, which is available only for Python 2.
How can I install pip with Python 3?

edit: Manual installation and use of setuptools is not the standard process anymore.
If you're running Python 2.7.9+ or Python 3.4+
Congrats, you should already have pip installed. If you do not, read onward.
If you're running a Unix-like System
You can usually install the package for pip through your package manager if your version of Python is older than 2.7.9 or 3.4, or if your system did not include it for whatever reason.
Instructions for some of the more common distros follow.
Installing on Debian (Wheezy and newer) and Ubuntu (Trusty Tahr and newer) for Python 2.x
Run the following command from a terminal:
sudo apt-get install python-pip
Installing on Debian (Wheezy and newer) and Ubuntu (Trusty Tahr and newer) for Python 3.x
Run the following command from a terminal:
sudo apt-get install python3-pip
Note:
On a fresh Debian/Ubuntu install, the package may not be found until you do:
sudo apt-get update
Installing pip on CentOS 7 for Python 2.x
On CentOS 7, you have to install setup tools first, and then use that to install pip, as there is no direct package for it.
sudo yum install python-setuptools
sudo easy_install pip
Installing pip on CentOS 7 for Python 3.x
Assuming you installed Python 3.4 from EPEL, you can install Python 3's setup tools and use it to install pip.
# First command requires you to have enabled EPEL for CentOS7
sudo yum install python34-setuptools
sudo easy_install pip
If your Unix/Linux distro doesn't have it in package repos
Install using the manual way detailed below.
The manual way
If you want to do it the manual way, the now-recommended method is to install using the get-pip.py script from pip's installation instructions.
Install pip
To install pip, securely download get-pip.py
Then run the following (which may require administrator access):
python get-pip.py
If setuptools is not already installed, get-pip.py will install setuptools for you.

I was able to install pip for python 3 on Ubuntu just by running sudo apt-get install python3-pip.

Python 3.4+ and Python 2.7.9+
Good news! Python 3.4 (released March 2014) ships with Pip. This is the best feature of any Python release. It makes the community's wealth of libraries accessible to everyone. Newbies are no longer excluded by the prohibitive difficulty of setup. In shipping with a package manager, Python joins Ruby, Nodejs, Haskell, Perl, Go--almost every other contemporary language with a majority open-source community. Thank you Python.
Of course, that doesn't mean Python packaging is problem solved. The experience remains frustrating. I discuss this at Does Python have a package/module management system?
Alas for everyone using an earlier Python. Manual instructions follow.
Python ≤ 2.7.8 and Python ≤ 3.3
Follow my detailed instructions at https://stackoverflow.com/a/12476379/284795 . Essentially
Official instructions
Per https://pip.pypa.io/en/stable/installing.html
Download get-pip.py, being careful to save it as a .py file rather than .txt. Then, run it from the command prompt.
python get-pip.py
You possibly need an administrator command prompt to do this. Follow http://technet.microsoft.com/en-us/library/cc947813(v=ws.10).aspx
For me, this installed Pip at C:\Python27\Scripts\pip.exe. Find pip.exe on your computer, then add its folder (eg. C:\Python27\Scripts) to your path (Start / Edit environment variables). Now you should be able to run pip from the command line. Try installing a package:
pip install httpie
There you go (hopefully)!

if you're using python 3.4+
just type:
python3 -m pip

For Ubuntu 12.04 or older,
sudo apt-get install python3-pip
won't work. Instead, use:
sudo apt-get install python3-setuptools ca-certificates
sudo easy_install3 pip

Update 2015-01-20:
As per https://pip.pypa.io/en/latest/installing.html the current way is:
wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py
I think that should work for any version
Original Answer:
wget http://python-distribute.org/distribute_setup.py
python distribute_setup.py
easy_install pip

Single Python in system
To install packages in Python always follow these steps:
If the package is for python 2.x: sudo python -m pip install [package]
If the package is for python 3.x: sudo python3 -m pip install [package]
Note: This is assuming no alias is set for python
Through this method, there will be no confusion regarding which python version is receiving the package.
Multiple Pythons/Virtual Envs
Say you have python3 ↔ python3.6 and python3.7 ↔ python3.7
To install for python3.6: sudo python3 -m pip install [package]
To instal for python3.7: sudo python3.7 -m pip install [package]
This is essentially the same method as shown previously.
Note 1
How to find which python? Do one of the following:
~ » python3 -c "import sys; print(sys.version)"
3.9.5 (default, Nov 18 2021, 16:00:48)
your python3 command spawns:
~ » python3
Python 3.9.5 (default, Nov 18 2021, 16:00:48)
[GCC 10.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
Notice python 3.9.5 in the second line.
or say you are using virtual env and see where your python points to:
» which python
/home/ganesh/os/np-test/bin/python
Note 2
Change what python3 or python points to: https://askubuntu.com/questions/320996/how-to-make-python-program-command-execute-python-3

python3 -m ensurepip
I'm not sure when exactly this was introduced, but it's installed pip3 for me when it didn't already exist.

Older version of Homebrew
If you are on macOS, use homebrew.
brew install python3 # this installs python only
brew postinstall python3 # this command installs pip
Also note that you should check the console if the install finished successfully. Sometimes it doesn't (e.g. an error due to ownership), but people simply overlook the log.
UPDATED - Homebrew version after 1.5
According to the official Homebrew page:
On 1st March 2018 the python formula will be upgraded to Python 3.x and a python#2 formula will be added for installing Python 2.7 (although this will be keg-only so neither python nor python2 will be added to the PATH by default without a manual brew link --force). We will maintain python2, python3 and python#3 aliases.
So to install Python 3, run the following command:
brew install python3
Then, the pip is installed automatically, and you can install any package by pip install <package>.

If your Linux distro came with Python already installed, you should be able to install PIP using your system’s package manager. This is preferable since system-installed versions of Python do not play nicely with the get-pip.py script used on Windows and Mac.
Advanced Package Tool (Python 2.x)
sudo apt-get install python-pip
Advanced Package Tool (Python 3.x)
sudo apt-get install python3-pip
pacman Package Manager (Python 2.x)
sudo pacman -S python2-pip
pacman Package Manager (Python 3.x)
sudo pacman -S python-pip
Yum Package Manager (Python 2.x)
sudo yum upgrade python-setuptools
sudo yum install python-pip python-wheel
Yum Package Manager (Python 3.x)
sudo yum install python3 python3-wheel
Dandified Yum (Python 2.x)
sudo dnf upgrade python-setuptools
sudo dnf install python-pip python-wheel
Dandified Yum (Python 3.x)
sudo dnf install python3 python3-wheel
Zypper Package Manager (Python 2.x)
sudo zypper install python-pip python-setuptools python-wheel
Zypper Package Manager (Python 3.x)
sudo zypper install python3-pip python3-setuptools python3-wheel

This is the one-liner I copy-and-paste:
curl https://bootstrap.pypa.io/get-pip.py | python3
Alternate:
curl -L get-pip.io | python3
From Installing with get-pip.py:
To install pip, securely download get-pip.py by following this link:
get-pip.py. Alternatively, use
curl:
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
Then run the following command in the folder where you have downloaded
get-pip.py:
python get-pip.py
Warning: Be cautious if you are using a Python install that is managed
by your operating system or another package manager. get-pip.py does
not coordinate with those tools, and may leave your system in an
inconsistent state.

If you use several different versions of python try using virtualenv http://www.virtualenv.org/en/latest/virtualenv.html#installation
With the advantage of pip for each local environment.
Then install a local environment in the current directory by:
virtualenv -p /usr/local/bin/python3.3 ENV --verbose
Note that you specify the path to a python binary you have installed on your system.
Then there are now an local pythonenvironment in that folder. ./ENV
Now there should be ./ENV/pip-3.3
use
./ENV/pip-3.3 freeze to list the local installed libraries.
use ./ENV/pip-3.3 install packagename to install at the local environment.
use ./ENV/python3.3 pythonfile.py to run your python script.

Here is my way to solve this problem at ubuntu 12.04:
sudo apt-get install build-essential libncursesw5-dev libssl-dev libgdbm-dev libc6-dev libsqlite3-dev tk-dev
Then install the python3 from source code:
wget https://www.python.org/ftp/python/3.4.0/Python-3.4.0.tar.xz
tar xvf Python-3.4.0.tar.xz
cd Python-3.4.0
./configure
make
make test
sudo make install
When you finished installing all of them, pip3 will get installed automatically.

This is what I did on OS X Mavericks to get this to work.
Firstly, have brew installed
Install python 3.4
brew install python3
Then I get the latest version of distribute:
wget https://pypi.python.org/packages/source/d/distribute/distribute-0.7.3.zip#md5=c6c59594a7b180af57af8a0cc0cf5b4a
unzip distribute-0.7.3.zip
cd distribute-0.7.3
sudo setup.py install
sudo easy_install-3.4 pip
sudo pip3.4 install virtualenv
sudo pip3.4 install virtualenvwrapper
mkvirtualenv py3
python --version
Python 3.4.1
I hope this helps.

pip is installed together when you install Python. You can use
sudo pip install (module)
or
python3 -m pip install (module).

Please follow below steps to install python 3 with pip:
Step 1 : Install Python from download here
Step 2 : you’ll need to download get-pip.py
Step 3 : After download get-pip.py , open your commant prompt and go to directory where your get-pip.py file saved .
Step 4 : Enter command python get-pip.py in cmd.
Step 5 : Pip installed successfully , Verify pip installation by type command in cmd pip --version

What’s New In Python 3.4
...
pip should always be available
...
By default, the commands pipX and pipX.Y will be installed on all platforms (where X.Y stands for the version of the Python installation), along with the pip Python package and its dependencies.
https://docs.python.org/3/whatsnew/3.4.html#whatsnew-pep-453
so if you have python 3.4 installed, you can just: sudo pip3 install xxx

For python3 try this:
wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py -O - | python
The good thing is that It will also detect what version of python you have (even if it's an environment of python in your custom location).
After this you can proceed normally with (for example)
pip install numpy
source:
https://pypi.python.org/pypi/setuptools/1.1.6#upgrading-from-setuptools-0-6

Assuming you are in a highly restricted computer env (such as myself) without root access or ability to install packages...
I had never setup a fresh/standalone/raw/non-root instance of Python+virtualenv before this post. I had do quite a bit of Googling to make this work.
Decide if you are using python (python2) or python3 and set your PATH correctly. (I am strictly a python3 user.) All commands below can substitute python3 for python if you are python2 user.
wget https://pypi.python.org/packages/source/v/virtualenv/virtualenv-x.y.z.tar.gz
tar -xzvf virtualenv-x.y.z.tar.gz
python3 virtualenv-x.y.z/virtualenv.py --python $(which python3) /path/to/new/virtualenv
source /path/to/new/virtualenv/bin/activate
Assumes you are using a Bourne-compatible shell, e.g., bash
Brilliantly, this virtualenv package includes a standalone version of pip and setuptools that are auto-magically installed into each new virtualenv. This solves the chicken and egg problem.
You may want to create an alias (or update your ~/.bashrc, etc.) for this final command to activate the python virtualenv during each login. It can be a pain to remember all these paths and commands.
Check your version of python now: which python3 should give: /path/to/new/virtualenv/bin/python3
Check pip is also available in the virtualenv via which pip... should give: /path/to/new/virtualenv/bin/pip
Then... pip, pip, pip!
Final tip to newbie Pythoneers: You don't think you need virtualenv when you start, but you will be happy to have it later. Helps with "what if" installation / upgrade scenarios for open source / shared packages.
Ref: https://virtualenv.pypa.io/en/latest/installation.html

To install pip, securely download get-pip.py.
Then run the following:
python get-pip.py
Be cautious if you're using a Python install that's managed by your
operating system or another package manager. get-pip.py does not
coordinate with those tools, and may leave your system in an
inconsistent state.
Refer: PIP Installation

And for Windows 8.1/10 OS Users just open cmd (command prompt)
write this : C:\Users\%USERNAME%\AppData\Local\Programs\Python\Python36-32\Scripts
then
just write this : pip3 install {name of package}
Hint: the location of folder Python36-32 may get different for new python 3.x versions

If you used the command "python get-pip.py", you should have the 'pip' function for Python3. However, 'pip' for Python2 might still be present. In my case I uninstalled 'pip', which removed it from Python2.
After that I ran "python get-pip.py" again. (Make sure that 'get-pip.py' is saved in the same folder as Python3.) The final step was to add the directory with 'pip' command to $PATH. That solved it for me.

=>Easy way to install Python any version on Ubuntu 18.04 or Ubuntu 20.04 follow these steps:-
Step 1: Update Local Repositories:-
sudo apt update
Step 2: Install Supporting Software:-
sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev wget
Step3: Create directory on your home directory To download the newest release of Python Source Code, navigate to the /python-source-files directory and use the wget command:-
mkdir python-source-files
Step 4: Download the Latest Version of Python Source Code:-
wget https://www.python.org/ftp/python/3.7.5/Python-3.7.5.tgz
"you can change python version by just modifies this:-"3.7.5" with the version you want example:-"3.5.2"
Step 5: Extract Compressed Files:-
tar –xf Python-3.7.5.tgz
or
tar xvzf Python-3.7.5.tgz
Step 6: Test System and Optimize Python:-
cd python-3.7.5 or your version of python.
Step 7: Now configure(Using the ––optimization option speeds code execution by 10-20%.):-
./configure ––enable–optimizations
OR you can also do this also if you facing ssl error:-
./configure --with-openssl
Step 8: Install a Second Instance of Python:-
sudo make altinstall
"It is recommended that you use the altinstall method. Your Ubuntu system may have software packages dependent on Python 2.x.
OR
If you want to Overwrite Default Python Installation/version:-
sudo make install"
Step 9:Now check Python Version:-
python3 ––version
Step 10: To install pip for python3 just go with this command:-
sudo apt-get install python3-pip

Trying to install an old python app, getting a libevent error

There is an old python app that I want to install on ubuntu.
When I run:
python setup.py install
I get this error:
/tmp/easy_install-s6CQJl/event-0.4.2/setup.py:23: UserWarning: Could not find libevent
warnings.warn("Could not find libevent")
event.c:4:20: fatal error: Python.h: No such file or directory
I have installed
build-essential
python-setuptools
libevent-dev
Is there something else I am missing?

event.c:4:20: fatal error: Python.h: No such file or directory
It looks like you need the Python development headers. Try
sudo apt-get install python-dev
Edit:
Hookbox can be successfully installed on Ubuntu 18.04 with a relatively modern Python 2.7. Here's a complete installation process:
Install OS-level dependencies
sudo add-apt-repository universe # Required for old libevent
sudo apt-get update
sudo apt-get install \
build-essential \
libevent1-dev \
libevent-1.4-2 \
python \
python-dev \
python-setuptools
Clone the source code somewhere convenient
git clone git://github.com/hookbox/hookbox.git
Install Hookbox
cd hookbox
# Ideally we should install Hookbox in a virtualenv
#
# Here is one way to do that
sudo apt-get install virtualenv
virtualenv env
source env/bin/activate
python setup.py install
If you use the virtualenv method outlined above you'll be able to run hookbox --help to see that it's working.
You can exit the virtualenv with deactivate (and still run hookbox by providing an absolute path to path/to/hookbox/env/bin/hookbox) and re-enter it with source path/to/hookbox/env/bin/activate, at which point hookbox should be on your $PATH.
If you choose not to use a virtualenv you'll need to use sudo python setup.py install here. That's not recommended as you'll be mixing manually installed Python packages with OS-supplied ones.

How to install the pyautogui module on RedHat

I've been using the Python module pyautogui on Windows where it is fairly simple to install and need to install it on a RedHat server for work.
The official documentation gives the following instructions for Linux installation:
pip3 install python3-xlib
sudo apt-get install scrot
sudo apt-get install python3-tk
sudo apt-get install python3-dev
pip3 install pyautogui
Now, two things bother me with this:
1) It assumes using Python 3 but we're using Python 2. Does it imply that the module only exists for Python 3 in Linux? Because I have been using it for Python 2 on Windows.
2) Dependency-wise, it assumes using Debian's package manager APT, certainly these dependencies should be available on a RedHat system with yum.
I first decided to install python-xlib which is the Python 2 version of the first package and it worked.
Secondly I tried:
sudo yum install scrot
Which resulted in the error "No package Scrot available". Finding a dead-end this way, I tried to manually download the sources for Scrot and install it.
I followed the instructions:
$ wget http://linuxbrit.co.uk/downloads/scrot-0.8.tar.gz
$ tar -xvf scrot-0.8.tar.gz
$ cd /scrot-0.8
$ ./configure --prefix=/usr
$ make
$ su -c "make install"
Which only resulted in getting the error
checking whether to enable maintainer-specific portions of Makefiles... no
checking for giblib-config... no
checking for giblib - version >= 1.2.3... no
*** The giblib-config script installed by giblib could not be found
*** If giblib was installed in PREFIX, make sure PREFIX/bin is in
*** your path, or set the GIBLIB_CONFIG environment variable to the
*** full path to giblib-config.
configure: error: Cannot find giblib: Is giblib-config in the path?
I found some threads addressing the issue and roughly asking to install giblib. However, I failed in doing so. Again, I only found instructions to install it in Debian-like systems and could not find out how to install it on a RedHat system. So now I'm trying to download and install the sources of giblib but this is beginning messy, especially given the fact that I'll have to ask that pyautogui to be installed on our production servers and I don't see myself explaining to my boss such a tremendous and bulky procedure. That would get rejected right away.
So I am now asking for help, a perhaps better or easier way to install the Python pyautogui moduke for Python 2 on a RedHat system. Or maybe even a similar module, I could not find any, as simple and efficient to use, alternative.
If someone could help me on this, that would be really helpful and would save me a lot of work and dead-ends.

I was facing the exact same issue, got into a loop of missing dependencies. Finally, someone helped me out, and it works.
yum install epel-release
yum install wget imlib2
wget http://packages.psychotic.ninja/7/base/x86_64/RPMS/scrot-0.8-12.el7.psychotic.x86_64.rpm
wget http://packages.psychotic.ninja/7/base/x86_64/RPMS/giblib-1.2.4-22.el7.psychotic.x86_64.rpm
rpm -Uvh giblib-1.2.4-22.el7.psychotic.x86_64.rpm
rpm -Uvh scrot-0.8-12.el7.psychotic.x86_64.rpm
And that's it. I was able to use PyAutoGUI after this.

I got scrot installed to Centos7 with following steps:
https://pkgs.org/:
Download & install:
giblib-devel-1.2.4-22.el7.psychotic.x86_64.rpm
giblib-1.2.4-22.el7.psychotic.x86_64.rpm
sudo yum --nogpgcheck localinstall
http://scrot.sourcearchive.com/downloads/0.8-8/:
Download:
scrot_0.8.orig.tar.gz
Install:
tar xvf scrot_0.8.orig.tar.gz
cd scrot-0.8/
./configure
make
sudo make install

I had a problem with Xlib in the install of PyAutoGUI with python 3 and somehow I managed to solve that problem and I want to share that here based on the question title "install the PyAutoGUI on linux RedHat"
error of installing PyAutoGUI with python 3 is something like this
Xlib.error.XauthError: ~/.Xauthority: [Error 2] No such file or directory: '/home/username/.Xauthority'
to install PyAutoGUI without error:
way 1 __
first, install Xlib
sudo yum install libX11
after that install this tow package
pip install PyUserInput
pip install PyAutoGUI
if that did not work for you, install python3-xlib before PyUserInput & PyAutoGUI
pip install python3-xlib
way 2 __
download (xvfb-run) from pkgs.org and install that with following command
rpm -ivh yourfile.rpm
then with help of xvfb-run you can install and even use PyAutoGUI code without error...
xvfb-run pip install PyAutoGUI
way 3 __
install one of this ( python3-xlib || python-xlib )
pip install python3-xlib
and then
export DISPLAY=:0
pip install PyAutoGUI

How to install poppler in ubuntu 15.04?

Poppler is a PDF rendering library based on the xpdf-3.0 code base.
I have already downloaded the tar.xz file from the official site http://poppler.freedesktop.org/
But I do not know what to do with this file
Is there any command to install or run?
P.S. - I am new to linux, so I don't know a lot about it yet..

Not sure how it worked in 15.04, but I know in 16.04 (Xenial), the package's official name is poppler-utils:
http://packages.ubuntu.com/xenial/poppler-utils
And thus can be installed with:
sudo apt-get install -y poppler-utils
The marked answer by codefreak is not correct if you need the poppler-command-line tools, such as pdftotext. Also, installing Python poppler via apt-get doesn't seem to play nice if you're on a customized system, e.g. one that is running off of the Anaconda distribution.

What you downloaded from poppler site is source code and you may not be expert enough to install it yourself. For such situations, Ubuntu and other linux distros manage packages of popular software so you don't have to go through manual installation via source code. In your case, poppler for python is available in package python-poppler which can be installed via Ubuntu's package manager apt.
To install poppler python bindings open terminal and run this:
sudo apt-get install python-poppler
You should have poppler available in python then.
To search for such packages in future you can do apt-cache search poppler. It will list down all packages you can install via apt.

Go to link below
https://www.ubuntuupdates.org/package/core/focal/main/base/poppler-utils
And only click appropriate box to install

so run these commands on you system
step 1 sudo apt-get update
step 2 sudo apt install -y software-properties-common
step 3 sudo apt update
step 4 sudo add-apt-repository main
step 5 sudo add-apt-repository universe
step 6 sudo add-apt-repository restricted
step 7 sudo add-apt-repository multiverse
step 8 apt-get install -y poppler-utils

Python3: ImportError: No module named '_ctypes' when using Value from module multiprocessing

I am using Ubuntu and have installed Python 2.7.5 and 3.4.0. In Python 2.7.5 I am able to successfully assign a variable x = Value('i', 2), but not in 3.4.0. I am getting:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python3.4/multiprocessing/context.py", line 132, in Value
from .sharedctypes import Value
File "/usr/local/lib/python3.4/multiprocessing/sharedctypes.py", line 10, in <
module>
import ctypes
File "/usr/local/lib/python3.4/ctypes/__init__.py", line 7, in <module>
from _ctypes import Union, Structure, Array
ImportError: No module named '_ctypes'
I just updated to 3.3.2 through installing the source of 3.4.0. It installed in /usr/local/lib/python3.4.
Did I update to Python 3.4 correctly?
One thing I noticed that Python 3.4 is installed in usr/local/lib, while Python 3.3.2 is still installed in usr/lib, so it was not overwritten.

Installing libffi-dev and re-installing python3.7 fixed the problem for me.
to cleanly build py 3.7 libffi-dev is required or else later stuff will fail
If using RHEL/Fedora:
yum install libffi-devel
or
sudo dnf install libffi-devel
If using Debian/Ubuntu:
sudo apt-get install libffi-dev

On a fresh Debian image, cloning https://github.com/python/cpython and running:
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
sudo apt-get install build-essential python-dev python-setuptools python-pip python-smbus
sudo apt-get install libncursesw5-dev libgdbm-dev libc6-dev
sudo apt-get install zlib1g-dev libsqlite3-dev tk-dev
sudo apt-get install libssl-dev openssl
sudo apt-get install libffi-dev
Now execute the configure file cloned above:
./configure
make # alternatively `make -j 4` will utilize 4 threads
sudo make altinstall
Got 3.7 installed and working for me.
SLIGHT UPDATE
Looks like I said I would update this answer with some more explanation and two years later I don't have much to add.
this SO post explains why certain libraries like python-dev might be necessary.
this SO post explains why one might use the altinstall as opposed to install argument in the make command.
Aside from that I guess the choice would be to either read through the cpython codebase looking for #include directives that need to be met, but what I usually do is keep trying to install the package and just keep reading through the output installing the required packages until it succeeds.
Reminds me of the story of the Engineer, the Manager and the Programmer whose car rolls down a hill.

If you use pyenv and get error "No module named '_ctypes'" (like i am) on Debian/Raspbian/Ubuntu you need to run this commands:
sudo apt-get install libffi-dev
pyenv uninstall 3.7.6
pyenv install 3.7.6
Put your version of python instead of 3.7.6

Detailed steps to install Python 3.7 in CentOS or any redhat linux machine:
Download Python from https://www.python.org/ftp/python/3.7.0/Python-3.7.0.tar.xz
Extract the content in new folder
Open Terminal in the same directory
Run below code step by step :
sudo yum -y install gcc gcc-c++
sudo yum -y install zlib zlib-devel
sudo yum -y install libffi-devel
./configure
make
make install

Thought I'd add the Centos installs:
sudo yum -y install gcc gcc-c++
sudo yum -y install zlib zlib-devel
sudo yum -y install libffi-devel
Check python version:
python3 -V
Create virtualenv:
virtualenv -p python3 venv

On my Ubuntu 18.04 machine, I had the common problem of python not finding _ctypes with the pyenv installed python.
In my case libffi-dev was already installed. Installing cpython from source, as suggested by #MikeiLL, didn't help either.
Turned out to be an homebrew issue.
ajkerrigans suggested solution on pyenvs github issues solved this problem for me.
Solution summary: Tell pyenv to build Python using the Homebrew-managed GCC, with a command like:
CC="$(brew --prefix gcc)/bin/gcc-11" \
pyenv install --verbose 3.10.0
This assumes that any build dependencies have also been installed via Homebrew as specified in the pyenv wiki. As of this writing, that looks like this for Homebrew on Linux:
brew install bzip2 libffi libxml2 libxmlsec1 openssl readline sqlite xz zlib

This solved the same error for me on Debian:
sudo apt-get install libffi-dev
and compile again
Reference: issue31652

None of the solution worked. You have to recompile your python again; once all the required packages were completely installed.
Follow this:
Install required packages
Run ./configure --enable-optimizations
https://gist.github.com/jerblack/798718c1910ccdd4ede92481229043be

I run into this error when I tried to install Python 3.7.3 in Ubuntu 18.04 with next command: $ pyenv install 3.7.3.
Installation succeeded after running $ sudo apt-get update && sudo apt-get install libffi-dev (as suggested here).
The issue was solved there.

Based on this answer, just copy-paste into the terminal.
First run:
sudo apt-get -y update
then:
sudo apt-get -y upgrade
sudo apt-get -y dist-upgrade
sudo apt-get -y install build-essential python-dev python-setuptools python-pip python-smbus
sudo apt-get -y install libncursesw5-dev libgdbm-dev libc6-dev
sudo apt-get -y install zlib1g-dev libsqlite3-dev tk-dev
sudo apt-get -y install libssl-dev openssl
sudo apt-get -y install libffi-dev
PS: You can just copy-paste the whole chunk into the terminal in one go.

In my case what was causing all sorts of Python installation issues including the one having to do with _ctypes and libffi was Homebrew on Linux / Linuxbrew. pyenv was happy again once brew was no longer in the $PATH.

Refer to this thread or this thread, for customized installation of libffi, it is difficult for Python3.7 to find the library location of libffi. An alternative method is to set the CONFIGURE_LDFLAGS variable in the Makefile, for example CONFIGURE_LDFLAGS="-L/path/to/libffi-3.2.1/lib64".

My solution:
Installing libffi-dev with apt-get didn't help.
But this helped: Installing libffi from source and then installing Python 3.8 from source.
My configuration:
Ubuntu 16.04 LTS
Python 3.8.2
Step by step:
I got the error message "ModuleNotFoundError: No module named '_ctypes'" when starting the debugger from Visual Studio Code, and when running python3 -c "import sklearn; sklearn.show_versions()".
download libffi v3.3 from https://github.com/libffi/libffi/releases
install libtool: sudo apt-get install libtool
The file README.md from libffi mentions that autoconf and automake are also necessary. They were already installed on my system.
configure libffi without docs:
./configure --disable-docs
make check
sudo make install
download python 3.8 from https://www.python.org/downloads/
./configure
make
make test
make install
After that my python installation could find _ctypes.

CentOS without root
Install libffi-3.2 (Do NOT use libffi-3.3)
wget ftp://sourceware.org/pub/libffi/libffi-3.2.tar.gz
tar -xzf libffi-3.2.tar.gz
cd libffi-3.2/
./configure --prefix=$YOUR_LIBFFI_DIR
make && make install
Install Python3
./configure --prefix=$YOUR_PATH/python/3.7.10 LDFLAGS=-L${YOUR_LIBFFI_DIR}/lib64 PKG_CONFIG_PATH=${YOUR_LIBFFI_DIR}/lib/pkgconfig --enable-shared
make && make install
Thanks for JohnWSteill

I was having the same problem. None of the above solutions worked for me. The key challenge was that I didn't have the root access. So, I first download the source of libffi. Then I compiled it with usual commands:
./configure --prefix=desired_installation_path_to_libffi
make
Then I recompiled python using
./configure --prefix=/home/user123/Softwares/Python/installation3/ LDFLAGS='-L/home/user123/Softwares/library/libffi/installation/lib64'
make
make install
In my case, 'home/user123/Softwares/library/libffi/installation/lib64' is path to LIBFFI installation directory where libffi.so is located. And, /home/user123/Softwares/Python/installation3/ is path to Python installation directory. Modify them as per your case.

If you don't mind using Miniconda, the necessary external libraries and _ctypes are installed by default. It does take more space and may require using a moderately older version of Python (e.g. 3.7.6 instead of 3.8.2 as of this writing).

You have to load the missing php3 (Python3) modules from the package manager.
If you have Ubuntu I recommend the Synaptic Package Manager:
sudo apt-get install synaptic
There you can simply search for the missing modules. search for ctypes and install all the packages. Then go to your Python dir and do
./configure
make install.
This should solve your problem.

How to install Python from source without libffi in /usr/local?
Download libffi from github and install to /path/to/local
Download python source code and compile with the following configuration:
export PKG_CONFIG_PATH=/path/to/local/lib/pkgconfig
./configure --prefix=/path/to/python \
LDFLAGS='-L/path/to/local/lib -Wl,-R/path/to/local/lib' \
--enable-optimizations
make
make install

I am using MAC M1 and I had this error:
... __boot__.py", line 30, in <module> import ctypes
and something was said about the file libffi.8.dylib
I downloaded this thing on Anaconda and now everything works:
https://anaconda.org/wakari/libffi
I inform you, since much of the above is either not for MAC or outdated, my Python is on Anaconda version 3.10.4
Application file created with py2app works now!!

If your issue is with the VSCODE DEBUGGER, check your currently selected python interpreter. I had both python3.10.9 and python3.10.6 installed; however, the former was probably missing some dependencies so I switched to the latter(my OS default interpreter) which solved the issue.
To change your python interpreter in VSCODE:
Hold ctrl+shift+P
Search Python:Select Interpreter and try your OS default version(The version you get when you run python3 --version
If the issue is still not resolved, run sudo apt-get install libffi-dev.

If you are doing something nobody here will listen you about because "you're doing it the wrong way", but you have to do it "the wrong way" for reasons too asinine to explain and also beyond your ability to control, you can try this:
Get libffi and install it into your user install area the usual way.
git clone https://github.com/libffi/libffi.git
cd libffi
./configure --prefix=path/to/your/install/root
make
make install
Then go back to your Python 3 source and find this part of the code in setup.py at the top level of the python source directory
ffi_inc = [sysconfig.get_config_var("LIBFFI_INCLUDEDIR")]
if not ffi_inc or ffi_inc[0] == '':
ffi_inc = find_file('ffi.h', [], inc_dirs)
if ffi_inc is not None:
ffi_h = ffi_inc[0] + '/ffi.h'
if not os.path.exists(ffi_h):
ffi_inc = None
print('Header file {} does not exist'.format(ffi_h))
ffi_lib = None
if ffi_inc is not None:
for lib_name in ('ffi', 'ffi_pic'):
if (self.compiler.find_library_file(lib_dirs, lib_name)):
ffi_lib = lib_name
break
ffi_lib="ffi" # --- AND INSERT THIS LINE HERE THAT DOES NOT APPEAR ---
if ffi_inc and ffi_lib:
ext.include_dirs.extend(ffi_inc)
ext.libraries.append(ffi_lib)
self.use_system_libffi = True
and add the line I have marked above with the comment. Why it is necessary, and why there is no way to get configure to respect '--without-system-ffi` on Linux platforms, perhaps I will find out why that is "unsupported" in the next couple of hours, but everything has worked ever since. Otherwise, best of luck... YMMV.
WHAT IT DOES: just overrides the logic there and causes the compiler linking command to add "-lffi" which is all that it really needs. If you have the library user-installed, it is probably detecting the headers fine as long as your PKG_CONFIG_PATH includes path/to/your/install/root/lib/pkgconfig.