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How to write header row with csv.DictWriter?
...ion "functionality", I'd prefer to code it myself; that way you can report ALL "extras" with the keys and values, not just the first extra key. What is a real nuisance with DictWriter is that if you've verified the keys yourself as each dict was being built, you need to remember to use extrasaction=...
class
...lass << foo syntax opens up foo's singleton class (eigenclass). This allows you to specialise the behaviour of methods called on that specific object.
a = 'foo'
class << a
def inspect
'"bar"'
end
end
a.inspect # => "bar"
a = 'foo' # new object, new singleton class
a.insp...
How to find event listeners on a DOM node when debugging or from the JavaScript code?
...d A.com/js/jquery-ui-1.10.3.custom.js?_=1384831682813. Origin B.com is not allowed by Access-Control-Allow-Origin.
– hiway
Nov 19 '13 at 3:50
5
...
What does “hashable” mean in Python?
...y and a set member, because these data structures use the hash value internally.
All of Python’s immutable built-in objects are hashable, while no mutable containers (such as lists or dictionaries) are. Objects which are instances of user-defined classes are hashable by default; they all comp...
CSS hack大全 - 创意 - 清泛网 - 专注C/C++及内核技术
...io:0){.bb{background-color:#f1ee18}}{} /* Safari(Chrome) 有效 */
@media all and (min-width: 0px){ .bb{background-color:#f1ee18;/*opera and Safari(Chrome) and firefox*/ background-color:#4cac70\0;}/* 仅 Opera 有效 */ }{}
.bb, x:-moz-any-link, x:default{background-color:#4eff00;/*IE7、Firef...
Performance difference for control structures 'for' and 'foreach' in C#
...t will depend on whether you're doing any real work in the loop. In almost all cases, the difference to performance won't be significant, but the difference to readability favours the foreach loop.
I'd personally use LINQ to avoid the "if" too:
foreach (var item in list.Where(condition))
{
}
EDI...
What is the best way to create constants in Objective-C
...he file in the Reddit-Prefix.pch file to make the constants available to all the files. Is it a good way of doing things? Also, I've done my research and found several methods to create constants, but I don't know which one to use:
...
What is a plain English explanation of “Big O” notation?
...a notation "Θ" (which is a two-side bound). In my experience, this is actually typical of discussions in non-academic settings. Apologies for any confusion caused.
Big O complexity can be visualized with this graph:
The simplest definition I can give for Big-O notation is this:
Big-O notation is ...
Sort Go map values by keys
...tween runs of the program. In practice, not only is it undefined, it's actually intentionally randomized. This is because it used to be predictable, and the Go language developers didn't want people relying on unspecified behavior, so they intentionally randomized it so that relying on this behavior...
How exactly does a generator comprehension work?
... generator expression is like a list comprehension, but instead of finding all the items you're interested and packing them into list, it waits, and yields each item out of the expression, one by one.
>>> my_list = [1, 3, 5, 9, 2, 6]
>>> filtered_list = [item for item in my_list i...