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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 ...
Using 'starts with' selector on individual class names
...ing space in there. Can one use boolean operators in a jquery selector? Ideally, the above would be 'OR' to avoid the (rare and likely avoidable) case where there are more than one class staring with 'apple-'
– DA.
Feb 1 '10 at 17:12
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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 is dynamic programming? [closed]
...ith dynamic programming, you store your results in some sort of table generally. When you need the answer to a problem, you reference the table and see if you already know what it is. If not, you use the data in your table to give yourself a stepping stone towards the answer.
The Cormen Algorithms ...
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...
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...
Why do you need to create a cursor when querying a sqlite database?
I'm completely new to Python's sqlite3 module (and SQL in general for that matter), and this just completely stumps me. The abundant lack of descriptions of cursor objects (rather, their necessity) also seems odd.
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How to create default value for function argument in Clojure
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A function can have multiple signatures if the signatures differ in arity. You can use that to supply default values.
(defn string->integer
([s] (string->integer s 10))
([s base] (Integer/parseInt s base)))
Note t...
Rails has_and_belongs_to_many migration
I have two models restaurant and user that I want to perform a has_and_belongs_to_many relationship.
4 Answers
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