You can use the environment markers to achieve this in requirements.txt since pip 6.0:
In many applications += and append are interchangeable, but for Python lists they are not.
Assignment statements in Python do not copy objects, they create bindings between a target and an object. For collections that are mutable or contain muta...
You probably know how to rewrite a for loop such as:
If you have a variable with a large memory footprint, you can force garbage collection using the gc Garbage Collector module: