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How to make my custom type to work with “range-based for loops”?
...hanges, and compilers that do not.
The objects returned do not have to actually be iterators. The for(:) loop, unlike most parts of the C++ standard, is specified to expand to something equivalent to:
for( range_declaration : range_expression )
becomes:
{
auto && __range = range_expressi...
How to write an inline IF statement in JavaScript?
...
Just to note, all parens in this case are optional. It is often personal preference/coding style that dictates when they are used.
– Will Klein
Apr 22 '12 at 18:46
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Unicode equivalents for \w and \b in Java regular expressions?
...cter class shorthand as "any letter, digit, or connecting punctuation" (usually: underscore). That way, a regex like \w+ matches words like hello , élève , GOÄ_432 or gefräßig .
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In Python, what is the difference between “.append()” and “+= []”?
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In general case append will add one item to the list, while += will copy all elements of right-hand-side list into the left-hand-side list.
Update: perf analysis
Comparing bytecodes we can assume that append version wastes cycles in LOAD_ATTR + CALL_FUNCTION, and += version -- in BUILD_LIST. App...
Changing every value in a hash in Ruby
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@Andrew Marshall Right you are, thanks. In Ruby 1.8, Hash.[] doesn't accept an array of array pairs, it requires an even number of direct arguments (hence the splat up front).
– Phrogz
Mar 4 '11 at 3...
How to tell if a tag failed to load
I'm dynamically adding <script> tags to a page's <head> , and I'd like to be able to tell whether the loading failed in some way -- a 404, a script error in the loaded script, whatever.
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How can the Euclidean distance be calculated with NumPy?
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There's a function for that in SciPy. It's called Euclidean.
Example:
from scipy.spatial import distance
a = (1, 2, 3)
b = (4, 5, 6)
dst = distance.euclidean(a, b)
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What exactly does += do in python?
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In Python, += is sugar coating for the __iadd__ special method, or __add__ or __radd__ if __iadd__ isn't present. The __iadd__ method of a class can do anything it wants. The list object implements it and uses it to iterate over an iterable object appending each...
LR性能测试结果样例分析 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...可以SiteScope工具，这个工具配置较为复杂，根据个人需要吧。我这里监控Tomcat使用的是ManageEngine Applications Manager 8的试用版，测试结束后得出Tomcat的JVM使用率如图1- 17所示。
图1- 17 Tomcat JVM使用率监视图
从图中我们可以明显...
How to get an object's properties in JavaScript / jQuery?
...Script's native for in loop:
var obj = {
foo: 'bar',
base: 'ball'
};
for(var key in obj) {
alert('key: ' + key + '\n' + 'value: ' + obj[key]);
}
or using jQuery's .each() method:
$.each(obj, function(key, element) {
alert('key: ' + key + '\n' + 'value: ' + element);
});
W...