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Makefile经典教程（入门必备） - C/C++ - 清泛网移动版 - 专注C/C++及内核技术
...定义的值。如：
foo = $(bar)
bar = $(ugh)
ugh = Huh?
all:
echo $(foo)
我们执行“make all”将会打出变量$(foo)的值是“Huh?”（ $(foo)的值是$(bar)，$(bar)的值是$(ugh)，$(ugh)的值是“Huh?”）可见，变量是可以使用后面的变量来...
How to get a random number in Ruby
...6). A roll in craps could be simulated with 2 + rand(6) + rand(6).
Finally, if you just need a random float, just call rand with no arguments.
As Marc-André Lafortune mentions in his answer below (go upvote it), Ruby 1.9.2 has its own Random class (that Marc-André himself helped to debug,...
How does Google's Page Speed lossless image compression work?
... image can be losslessly compressed, and provide a link to download this smaller image.
9 Answers
...
Restore the state of std::cout after manipulating it
...lude <iostream> or #include <ios> then when required:
std::ios_base::fmtflags f( cout.flags() );
//Your code here...
cout.flags( f );
You can put these at the beginning and end of your function, or check out this answer on how to use this with RAII.
...
_csv.Error: field larger than field limit (131072)
...
The csv file might contain very huge fields, therefore increase the field_size_limit:
import sys
import csv
csv.field_size_limit(sys.maxsize)
sys.maxsize works for Python 2.x and 3.x. sys.maxint would only work with Python 2.x (SO: what-is-sys-maxint-in-python-3)
Update
As Geoff pointed out,...
Setting variable to NULL after free
... int *nPtr=NULL;. Now, I would agree that this would be redundant, with a malloc following right in the next line. However, if there is code between the declaration and the first initialization, somebody might start using the variable even though it has no value yet. If you null-initialize, you get ...
How to play a local video with Swift?
...
class ViewController: UIViewController {
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
playVideo()
}
private func playVideo() {
guard let path = Bundle.main.path(forResource: "video", ofType:"m4v") else {
debugPrint("...
How to pass an array within a query string?
...s[]" value="Mercedes">
NOTE: Using field[] for multiple values is really poorly documented. I don't see any mention of it in the section on multi-valued keys in Query string - Wikipedia, or in the W3C docs dealing with multi-select inputs.
UPDATE
As commenters have pointed out, this is ve...
Replace only some groups with Regex
...attern = @"-(\d+)-";
var replaced = Regex.Replace(text, pattern, (_match) =>
{
Group group = _match.Groups[1];
string replace = "AA";
return String.Format("{0}{1}{2}", _match.Value.Substring(0, group.Index - _match.Index), replace, _match.Value...
CoffeeScript, When to use fat arrow (=>) over arrow (->) and vice versa
When building a class in CoffeeScript, should all the instance method be defined using the => ("fat arrow") operator and all the static methods being defined using the -> operator?
...