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Is Java really slow?
... to a self-fulfilling prophecy -- when people care about speed, they often select C++ because it has that reputation. They put extra time and effort into optimization, and a new generation of fast C++ code is written.
To summarize, the normal implementation of Java makes maximum optimization proble...
What is the proper way to re-attach detached objects in Hibernate?
...k);
});
And Hibernate is going to execute the following SQL statements:
SELECT
b.id,
b.author AS author2_0_,
b.isbn AS isbn3_0_,
b.title AS title4_0_
FROM
book b
WHERE
b.id = 1
-- Merging the Book entity
UPDATE
book
SET
author = 'Vlad Mihalcea',
isbn = '978-9...
Failure [INSTALL_FAILED_ALREADY_EXISTS] when I tried to update my application
...lease variant
Bonus
I set up an alias in my ~/.bash_profile, to make it a 2char command.
alias bi="gradlew && adb install -r exampleApp.apk"
(Short for Build and Install)
share
|
improve th...
How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly
... 0.0 NaN 0.0
3 0.0 1.0 2.0 3.0
4 NaN 0.0 NaN NaN
If you want to select the rows that have two or more columns with null value, you run the following:
>>> qty_of_nuls = 2
>>> df.iloc[df[(df.isnull().sum(axis=1) >=qty_of_nuls)].index]
0 1 2 3
1 0.0 NaN 0...
MySQL: Transactions vs Locking Tables
...ransactions vs locking tables to ensure database integrity and make sure a SELECT and UPDATE remain in sync and no other connection interferes with it. I need to:
...
Default implementation for Object.GetHashCode()
...sually more interested in whether a string containing the same sequence of characters has already been added. That's why string overrides GetHashCode. On the other hand, suppose you want to keep a count of how many times various controls process Paint events. You could use a Dictionary<Object,...
Remove duplicated rows
...tes, right? Or it removes values randomly?
– News_is_Selection_Bias
Aug 7 '17 at 0:43
@alphabetagamma yes, it keeps th...
Best Practice: Access form elements by HTML id or name attribute?
... restrictions on the value of the name attribute, so e.g. you can have <select name="a+b"> or <input type="text" name="...2">, which can't be referenced using javascript .propertyName notation). Explicit [] notation also allows names built from expressions, e.g. myCheckBox = document.ge...
Can we write our own iterator in Java?
If I have a list containing [alice, bob, abigail, charlie] and I want to write an iterator such that it iterates over elements that begin with 'a', can I write my own ? How can I do that ?
...
Union Vs Concat in Linq
...ence is not changed.
If you will override Equals and GetHashCode (used to select distinct items), then items will not be compared by reference:
class X
{
public int ID { get; set; }
public override bool Equals(object obj)
{
X x = obj as X;
if (x == null)
re...