Python 101 : Naming style - Underscores and double underscores -


Names that start and end with two underscores - __var__ - are internal names used by python like - __init__, __str__ -.

Names that start with an underscore - _var - are not imported into other programs using the - from ... import ... - instruction.
They are meant to be used within the program as "internals":


Names that start with two underscores - __var - inside a class get prefixed with the class name:


The "__var" variable becomes "_A__var".

The name that is represented by single underscore - _ - is used by python to store the result of the last result, for example to go through a loop where the index is of no use to us:


Names with a trailing underscore - var_ - are usually used so the name doesn't get mixed up with a python keyword.

Comments

Post a Comment

Popular posts from this blog

Istio 101 : How Istio ServiceEntry relates to Kubernetes Services and Endpoints

Image
Kubernetes "converts" its services and pods/endpoints into a ServiceEntry through Istio .   A service with two pods and two endpoints -  10.244.3.1, 10.244.3.2 -,  will be mapped to a ServiceEntry - host / IP address endpoint -. Endpoints  represent the IP addresses that a service sends its requests to. The "hosts" in the  ServiceEntry   Yaml file are associated with the service. A ServiceEntry adds newly added services to the service registry - database of existing services in Istio -, this allows existing services to be able to access these newly deployed ones. Below is an example of a service its endpoint and the resulting service entry : We have two nginx pods and the service entry that allows access through the host " service1.default.svc.cluster.local " to  the nginx applications.
Read more

Kubernetes 101 : - Scaling a Stateful set -

Image
The below diagram represents the scaling down of a  statefulset named  db1 : Before scaling down our statefulset , we check the pods and we see that there are three replicas: We can tell from the names of our pods that they are managed by a  statefulset is named  db1 . We look for that statefulset in our system using the below: Then we can scale out statefulset down to two pods using the below command: We check to see if the statefulset was successfully scaled down to two pods using the following: Remark: The " --record " parameter created an annotation as we see using the " kubectl describe " command:
Read more

Python 101 : Generators and Lists

Image
A list is a collection of val ues stored in memory. A generator does not build a list, it only tells us how to generate these values with nothing stored in memory. Our examples below use the " range() " iterator and they produce the same results. Below is our list example: And our generator example: The generator expression generate values only when they are needed which saves us system resources, especially with huge amounts of data.
Read more