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Split data frame string column into multiple columns
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Use stringr::str_split_fixed
library(stringr)
str_split_fixed(before$type, "_and_", 2)
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What does “Document-oriented” vs. Key-Value mean when talking about MongoDB vs Cassandra?
What does going with a document based NoSQL option buy you over a KV store, and vice-versa?
4 Answers
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Dynamic instantiation from string name of a class in dynamically imported module?
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You can use getattr
getattr(module, class_name)
to access the class. More complete code:
module = __import__(module_name)
class_ = getattr(module, class_name)
instance = class_()
As mentioned below, we may use importlib
import importlib
module = importlib.imp...
Storyboard - refer to ViewController in AppDelegate
...ly from the AppDelegate? I've made a variable with the relevant class and turned it into an IBOutlet property, but I don't see any way of being able to refer to the new ViewController in code - any attempt to ctrl-drag a connection doesn't work.
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What is the difference between an interface and abstract class?
...'t do anything. It's just a pattern.
For example (pseudo code):
// I say all motor vehicles should look like this:
interface MotorVehicle
{
void run();
int getFuel();
}
// My team mate complies and writes vehicle looking that way
class Car implements MotorVehicle
{
int fuel;
vo...
How can I use redis with Django?
I've heard of redis-cache but how exactly does it work? Is it used as a layer between django and my rdbms, by caching the rdbms queries somehow?
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What is the difference between JAX-RS and JAX-WS?
After reading a few articles about JAX-RS and JAX-WS, I had a few questions that I want to confirm?
5 Answers
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How to declare std::unique_ptr and what is the use of it?
I try to understand how std::unique_ptr works and for that I found this document. The author starts from the following example:
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Django CharField vs TextField
...the difference between CharField() and TextField() in Django? The documentation says that CharField() should be used for smaller strings and TextField() should be used for larger strings. Okay, but where is the line drawn between "small" and "large"? What's going on under the hood here ...
Create a tar.xz in one command
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Use the -J compression option for xz. And remember to man tar :)
tar cfJ <archive.tar.xz> <files>
Edit 2015-08-10:
If you're passing the arguments to tar with dashes (ex: tar -cf as opposed to tar cf), then th...