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Remove characters except digits from string using Python?
How can I remove all characters except numbers from string?
15 Answers
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How to check whether an object has certain method/property?
...much any modern dynamic scripting language (Python, Javascript, VB script, PHP, Lua... I could go on and on). It's not a bug, it's a feature.
– Tim Keating
Dec 3 '11 at 14:36
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What is the copy-and-swap idiom?
...s arguably the most nuanced and difficult. How should it be done? What pitfalls need to be avoided?
The copy-and-swap idiom is the solution, and elegantly assists the assignment operator in achieving two things: avoiding code duplication, and providing a strong exception guarantee.
How does it wor...
JavaScript: What are .extend and .prototype used for?
...ate ).lol() // alert message
In the snippet above, I define a method for all Date objects ( already existing ones and all new ones ).
extend is usually a high level function that copies the prototype of a new subclass that you want to extend from the base class.
So you can do something like:
e...
Flask-SQLAlchemy import/context issue
...:
# fields here
pass
And then in your application setup you can call init_app:
# apps.application.py
from flask import Flask
from apps.members.models import db
app = Flask(__name__)
# later on
db.init_app(app)
This way you can avoid cyclical imports.
This pattern does not necessitate ...
How to update PATH variable permanently from Windows command line?
... do this can be found on MSDN. The key extract is this:
To programmatically add or modify system environment variables, add them to the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment registry key, then broadcast a WM_SETTINGCHANGE message with lParam set to the s...
Removing duplicates from a list of lists
... much easier that it offers good returns on efforts. But sometimes (essentially for "tragically crucial bottlenecks" in deep inner loops of code that's pushing the boundaries of performance limits) one may need to go into much more detail, providing probability distributions, deciding which performa...
What is the purpose of willSet and didSet in Swift?
... for instance to notify other objects that the property just changed. When all you have is get/set, you need another field to hold the value. With willSet and didSet, you can take action when the value is modified without needing another field. For instance, in that example:
class Foo {
var myP...
How does Trello access the user's clipboard?
...source code Trello uses to accomplish the clipboard trick.
We don't actually "access the user's clipboard", instead we help the user out a bit by selecting something useful when they press Ctrl+C.
Sounds like you've figured it out; we take advantage of the fact that when you want to hit Ctrl+C, ...
Timeout on a function call
I'm calling a function in Python which I know may stall and force me to restart the script.
18 Answers
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