How to install only uninstalled applications via pip install -r requirements txt?

D

Dmitry Vyatkin2015-12-03 00:20:17

Django

Dmitry Vyatkin, 2015-12-03 00:20:17

When I run the command, it downloads and installs applications, but how to check if the application is installed and install only those that are not installed?

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marazmiki, 2015-12-03
@dim137

Generally speaking, pip does just that—it installs a package only if the specified requirement is not met:

(.virtualenv) $ pip freeze > requirements.txt
(.virtualenv) $ pip install -r requirements.txt 
Requirement already satisfied (use --upgrade to upgrade): Django==1.9 in ./.virtualenv/lib/python3.4/site-packages (from -r requirements.txt (line 2))
Requirement already satisfied (use --upgrade to upgrade): dj-database-url==0.3.0 in ./.virtualenv/lib/python3.4/site-packages (from -r requirements.txt (line 3))
Requirement already satisfied (use --upgrade to upgrade): psycopg2==2.6.1 in ./.virtualenv/lib/python3.4/site-packages (from -r requirements.txt (line 4))
Requirement already satisfied (use --upgrade to upgrade): wheel==0.26.0 in ./.virtualenv/lib/python3.4/site-packages (from -r requirements.txt (line 5))
Cleaning up...

Maybe you have an old package installed, like package-name==0.1, but requirements.txt says something complicated like package-name>=0.3,<0.4? Or a dev repository that is downloaded from git?