CentOS7 install python3 and pip3

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Environmental information###

Operating system: CentOS Linux release 7.6.1810
Python：3.7.4

Status description###

The current CentOS system comes with python2.7.5, because yum will use python2, so it cannot be deleted. After installing python3 this time, keep the two versions coexisting for a long time.

This installation uses the method of downloading the python source code and compiling;

Steps###

Log in to CentOS as root, and the following operations are in the default ~ directory:

1. Yum update:

yum update -y

1. Install the necessary software:

yum -y install \
zlib-devel \
bzip2-devel \
openssl-devel \
ncurses-devel \
sqlite-devel \
readline-devel \
tk-devel \
libffi-devel \
wget \
gcc \
make

1. Download the python3.7.4 source code:

wget https://www.python.org/ftp/python/3.7.4/Python-3.7.4.tgz

1. Unzip:

tar -zxvf Python-3.7.4.tgz

1. Enter the decompressed directory and perform the configure operation before compilation:

cd Python-3.7.4&&./configure prefix=/usr/local/python3

1. To compile the source code, execute the following command in the Python-3.7.4 directory:

make && make install

After successful compilation, the following message is displayed, and both setuptools and pip have been deployed successfully:

Collecting setuptools
Collecting pip
Installing collected packages: setuptools, pip
Successfully installed pip-19.0.3 setuptools-40.8.0

1. Create a link to python3:

ln -s /usr/local/python3/bin/python3.7/usr/bin/python3

1. Create a link to pip3:

ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3

1. pip3 upgrade

pip3 install --upgrade pip

At this point, the installation is complete, and then simply verify

verification###

1. The simple operation is as follows, it can be seen that python3 is installed successfully:

[ root@python3 ~]# python3 --version
Python 3.7.4[root@python3 ~]# pip3 --version
pip 19.1.1from/usr/local/python3/lib/python3.7/site-packages/pip(python 3.7)[root@python3 ~]# python3
Python 3.7.4(default, Jul 202019,11:35:19)[GCC 4.8.520150623(Red Hat 4.8.5-36)] on linux
Type "help","copyright","credits" or "license"for more information.>>>print("Hello world")
Hello world

Press Ctrl+d to exit python3 dialogue mode
2. Install Flask:

pip3 install Flask

The console outputs the following information, indicating that Flask is installed successfully:

[ root@python3 ~]# pip3 install Flask
Collecting Flask
 Downloading https://files.pythonhosted.org/packages/9b/93/628509b8d5dc749656a9641f4caf13540e2cdec85276964ff8f43bbb1d3b/Flask-1.1.1-py2.py3-none-any.whl(94kB)|████████████████████████████████| 102kB 431kB/s 
Collecting itsdangerous>=0.24(from Flask)
 Downloading https://files.pythonhosted.org/packages/76/ae/44b03b253d6fade317f32c24d100b3b35c2239807046a4c953c7b89fa49e/itsdangerous-1.1.0-py2.py3-none-any.whl
Collecting click>=5.1(from Flask)
 Downloading https://files.pythonhosted.org/packages/fa/37/45185cb5abbc30d7257104c434fe0b07e5a195a6847506c074527aa599ec/Click-7.0-py2.py3-none-any.whl(81kB)|████████████████████████████████| 81kB 1.3MB/s 
Collecting Jinja2>=2.10.1(from Flask)
 Downloading https://files.pythonhosted.org/packages/1d/e7/fd8b501e7a6dfe492a433deb7b9d833d39ca74916fa8bc63dd1a4947a671/Jinja2-2.10.1-py2.py3-none-any.whl(124kB)|████████████████████████████████| 133kB 1.8MB/s 
Collecting Werkzeug>=0.15(from Flask)
 Downloading https://files.pythonhosted.org/packages/d1/ab/d3bed6b92042622d24decc7aadc8877badf18aeca1571045840ad4956d3f/Werkzeug-0.15.5-py2.py3-none-any.whl(328kB)|████████████████████████████████| 337kB 3.4MB/s 
Collecting MarkupSafe>=0.23(from Jinja2>=2.10.1->Flask)
 Downloading https://files.pythonhosted.org/packages/98/7b/ff284bd8c80654e471b769062a9b43cc5d03e7a615048d96f4619df8d420/MarkupSafe-1.1.1-cp37-cp37m-manylinux1_x86_64.whl
Installing collected packages: itsdangerous, click, MarkupSafe, Jinja2, Werkzeug, Flask
Successfully installed Flask-1.1.1 Jinja2-2.10.1 MarkupSafe-1.1.1 Werkzeug-0.15.5 click-7.0 itsdangerous-1.1.0

1. Create a file named hello.py with the following content:

from flask import Flask

app =Flask(__name__)

@ app.route('/')
def hello():return'Hello flask'if __name__ =='__main__':
  app.run(host='0.0.0.0',port=5000,debug=True)

1. Run the script:

python3 hello.py

1. The IP address of the current CentOS computer is 192.168.121.134. When you visit: in the browser, the response is shown in the following figure:

So far, python3 and pip3 have all been verified.