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How to access environment variable values?
I set an environment variable that I want to access in my Python application. How do I get its value?
12 Answers
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Why do we need a pure virtual destructor in C++?
... that takes a Fruit class pointer.
Virtual functions are, firstly, a run-time thing. It is part of polymorphism in that it is used to decide which function to run at the time it is called in the running program.
The virtual keyword is a compiler directive to bind functions in a certain order if ...
Self-references in object literals / initializers
...e foo is beeing declared as a variable and c will only be evaluated at the time it is invoked, using foo inside c will work, as opposed to this (be careful though)
– Bernardo Dal Corno
Apr 19 '18 at 20:11
...
Asking the user for input until they give a valid response
...seful to put this code in a function, so you don't have to retype it every time.
def get_non_negative_int(prompt):
while True:
try:
value = int(input(prompt))
except ValueError:
print("Sorry, I didn't understand that.")
continue
if va...
Using ls to list directories and their total sizes
Is it possible to use ls in Unix to list the total size of a sub-directory and all its contents as opposed to the usual 4K that (I assume) is just the directory file itself?
...
Android: AsyncTask vs Service
...ter suited to a task than the other.
AsyncTasks are designed for once-off time-consuming tasks that cannot be run of the UI thread. A common example is fetching/processing data when a button is pressed.
Services are designed to be continually running in the background. In the example above of fetc...
Automatically deleting related rows in Laravel (Eloquent ORM)
...
Note: I spend some time until I got this working. I needed to add first() into the query so I could access the model-event e.g. User::where('id', '=', $id)->first()->delete(); Source
– Michel Ayres
M...
Why use Ruby's attr_accessor, attr_reader and attr_writer?
...resting. For Ruby 1.8.7, the attr_reader defined accesor takes 86% of the time that the manually defined accessor does. For Ruby 1.9.0, the attr_reader defined accessor takes 94% of the time that the manually defined accessor does. In all of my tests, however, accessors are fast: an accessor take...
What is Node.js' Connect, Express and “middleware”?
...ong about the accepted answer
These might have been true as some point in time, but wrong now:
that inherits an extended version of http.Server
Wrong. It doesn't extend it and as you have seen ... uses it
Express does to Connect what Connect does to the http module
Express 4.0 doesn't ...
How to terminate a Python script
...nly Kenny will die and Cartman will live forever.
import threading
import time
import sys
import os
def kenny(num=0):
if num > 3:
# print("Kenny dies now...")
# raise SystemExit #Kenny will die, but Cartman will live forever
# sys.exit(1) #Same as above
prin...