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Why '&&' and not '&'?
...at the evaluation is canceled as soon as the result is clear.
Example:
if(CanExecute() && CanSave())
{
}
If CanExecute returns false, the complete expression will be false, regardless of the return value of CanSave. Because of this, CanSave is not executed.
This is very handy in the f...
File Upload ASP.NET MVC 3.0
... public ActionResult Index(HttpPostedFileBase file)
{
// Verify that the user selected a file
if (file != null && file.ContentLength > 0)
{
// extract only the filename
var fileName = Path.GetFileName(file.FileName);
// s...
cleanest way to skip a foreach if array is empty [duplicate]
Not a major problem but I was wondering if there is a cleaner way to do this. It would be good to avoid nesting my code with an unnecessary if statement. If $items is empty php throws an error.
...
计算统计特征（正态分布）函数及实例 - C/C++ - 清泛网 - 专注C/C++及内核技术
....end(),
[](const std::pair<int, int> &pr) { return pr.second; });
//if (value > stdev_info._ave * 2) { ... }
return 0;
}
stdev.h
#ifndef _UTILITY_STDEV_H_
#define _UTILITY_STDEV_H_
/*
* 计算统计特征的函数
*/
#define _USE_MATH_DEFINES
#include <algorithm>
#includ...
Check if the number is integer
... was surprised to learn that R doesn't come with a handy function to check if the number is integer.
12 Answers
...
Check if a class is derived from a generic class
...heck.IsGenericType ? toCheck.GetGenericTypeDefinition() : toCheck;
if (generic == cur) {
return true;
}
toCheck = toCheck.BaseType;
}
return false;
}
share
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...
Shortest distance between a point and a line segment
... const float l2 = length_squared(v, w); // i.e. |w-v|^2 - avoid a sqrt
if (l2 == 0.0) return distance(p, v); // v == w case
// Consider the line extending the segment, parameterized as v + t (w - v).
// We find projection of point p onto the line.
// It falls where t = [(p-v) . (w-v)] /...
How to check if an email address exists without sending an email?
...
There are two methods you can sometimes use to determine if a recipient actually exists:
You can connect to the server, and issue a VRFY command. Very few servers support this command, but it is intended for exactly this. If the server responds with a 2.0.0 DSN, the user exists.
...
How to get the caret column (not pixels) position in a textarea, in characters, from the start?
..., so you will have to do something like this:
function getCaret(node) {
if (node.selectionStart) {
return node.selectionStart;
} else if (!document.selection) {
return 0;
}
var c = "\001",
sel = document.selection.createRange(),
dul = sel.duplicate(),
len = 0;
...
How to implement a binary tree?
...f getRoot(self):
return self.root
def add(self, val):
if self.root is None:
self.root = Node(val)
else:
self._add(val, self.root)
def _add(self, val, node):
if val < node.v:
if node.l is not None:
self._...