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Difference between size_t and std::size_t
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90
C's size_t and C++'s std::size_t are both same.
In C, it's defined in <stddef.h> and in ...
Java HashMap performance optimization / alternative
...ted out the hashCode() method was to blame. It was only generating around 20,000 codes for 26 million distinct objects. That is an average of 1,300 objects per hash bucket = very very bad. However if I turn the two arrays into a number in base 52 I am guaranteed to get a unique hash code for every o...
Clearing all cookies with JavaScript
...ookies() {
var cookies = document.cookie.split(";");
for (var i = 0; i < cookies.length; i++) {
var cookie = cookies[i];
var eqPos = cookie.indexOf("=");
var name = eqPos > -1 ? cookie.substr(0, eqPos) : cookie;
document.cookie = name + "=;expires=Thu, ...
How to force R to use a specified factor level as reference in a regression?
... the relevel() function. Here is an example:
set.seed(123)
x <- rnorm(100)
DF <- data.frame(x = x,
y = 4 + (1.5*x) + rnorm(100, sd = 2),
b = gl(5, 20))
head(DF)
str(DF)
m1 <- lm(y ~ x + b, data = DF)
summary(m1)
Now alter the factor b in DF by use of th...
Is there a way to programmatically scroll a scroll view to a specific edit text?
...e
public void run() {
your_scrollview.scrollTo(0, your_EditBox.getBottom());
}
});
}
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Floating View 扩展：悬浮视图扩展，将组件转换为悬浮窗口 · App Inventor 2 中文网
...应用等。
包名：com.jdl.FloatingView
版本：1.2
发布日期：2020年6月14日
最后更新：2020年6月28日
作者：Jarlisson
文件大小：20.2 KB
下载链接
扩展文件：
com.jdl.FloatingView.aix
示例文件：
FloatingView.aia
功能...
How to git-svn clone the last n revisions from a Subversion repository?
... start your clone at ( -r$REV:HEAD).
For example: git svn clone -s -r1450:HEAD some/svn/repo
Git's data structure is based on pointers in a directed acyclic graph (DAG), which makes it trivial to walk back n commits. But in SVN ( and therefore in Git-SVN) you will have to find the revision num...
What's the longest possible worldwide phone number I should consider in SQL varchar(length) for phon
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80
Well considering there's no overhead difference between a varchar(30) and a varchar(100) if you'...
Why does sys.exit() not exit when called inside a thread in Python?
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edited Dec 10 '19 at 22:37
Richard
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Does MySQL ignore null values on unique constraints?
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440
Yes, MySQL allows multiple NULLs in a column with a unique constraint.
CREATE TABLE table1 (x I...