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Difference between freeze and seal
...rn false
It makes every existing property non-configurable: they cannot be converted from 'data descriptors' to 'accessor descriptors' (and vice versa), and no attribute of accessor descriptors can be modified at all (whereas data descriptors can change their writable attribute, and their value attr...
Comparing two dataframes and getting the differences
... lists, to do it efficiently we should first order them then compare them (converting the list to sets/hashing would also be fast; both are an incredible improvement to the simple O(N^2) double comparison loop
Note: the following code produces the tables:
df1=pd.DataFrame({
'Date':['2013-11-24...
Why does appending “” to a String save memory?
...owing:
data.substring(x, y) + ""
creates a new (smaller) String object, and throws away the reference to the String created by substring(), thus enabling garbage collection of this.
The important thing to realise is that substring() gives a window onto an existing String - or rather, the charac...
Laravel Check If Related Model Exists
...$relation) is a general solution for all relations. It will work for Model and Collection, while Model has no ->count() method.
– Jarek Tkaczyk
Jul 29 '14 at 17:16
8
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JavaScript + Unicode regexes
...mall Java program that uses its own native Unicode support).
Basically it converts \p{...} to a range of values, much like the output of the tool mentioned by Tomalak, but the intervals can end up quite large (since it's not dealing with blocks, but with characters scattered through many different ...
MySQL: @variable vs. variable. What's the difference?
...are loosely typed variables that may be initialized somewhere in a session and keep their value until the session ends.
They are prepended with an @ sign, like this: @var
You can initialize this variable with a SET statement or inside a query:
SET @var = 1
SELECT @var2 := 2
When you develop a stor...
How do I implement an Objective-C singleton that is compatible with ARC?
How do I convert (or create) a singleton class that compiles and behaves correctly when using automatic reference counting (ARC) in Xcode 4.2?
...
“for loop” with two variables? [duplicate]
...other set (Note that if your lists contains other lists, you might want to convert the inner lists to tuples first so that they are hashable; otherwise the call to set will fail.). The list function then turns the set back into a list.
UPDATE 2
OR, the OP might want elements that are identical in...
Best way to split string into lines
...ible solutions I prefer the one using regular expressions since only that handles all source platforms correctly.
– Konrad Rudolph
Jan 20 '11 at 17:14
...
Are nested try/except blocks in python a good programming practice?
...more complicated situations you may be right, but I think that when you're converting between exception types you often know that the details of the first exception don't matter to the outside user. That is, if __getattr__ raises an exception the bug is probably a typo in the attribute access, not a...