大约有 10,000 项符合查询结果（耗时：0.0122秒） [XML]
How to make rounded percentages add up to 100%
... properly, here's my semi-obfuscated version using underscorejs:
function foo(l, target) {
var off = target - _.reduce(l, function(acc, x) { return acc + Math.round(x) }, 0);
return _.chain(l).
sortBy(function(x) { return Math.round(x) - x }).
map(function(x, i) { re...
Is std::vector copying the objects with a push_back?
...o exactly what you want. My favorite idiom is typedef boost::shared_ptr<Foo> FooPtr; Then make containers of FooPtrs
– pm100
Feb 16 '10 at 18:00
...
Is R's apply family more than syntactic sugar?
...y, but you also specify the return value type which makes it much faster.
foo <- function(x) x+1
y <- numeric(1e6)
system.time({z <- numeric(1e6); for(i in y) z[i] <- foo(i)})
# user system elapsed
# 3.54 0.00 3.53
system.time(z <- lapply(y, foo))
# user system elaps...
Get keys from HashMap in Java
...than one key. You can use keySet() to get the set of all keys.
team1.put("foo", 1);
team1.put("bar", 2);
will store 1 with key "foo" and 2 with key "bar". To iterate over all the keys:
for ( String key : team1.keySet() ) {
System.out.println( key );
}
will print "foo" and "bar".
...
Make multiple-select to adjust its height to fit options without scroll bar
...tiple='multiple' id='select' style='overflow:hidden'>
<option value='foo'>foo</option>
<option value='bar'>bar</option>
<option value='abc'>abc</option>
<option value='def'>def</option>
<option value='xyz'>xyz</option>
</select>
...
How does the Java 'for each' loop work?
...not implement Iterable so you can't for(String s : (Iterator<String>)foo). I understand why this is, but it is irritating.
– Christopher Schultz
Oct 18 '19 at 20:21
...
What would be C++ limitations compared C language? [closed]
...itrary subset of C++. C is not a subset of C++ at all.
This is valid C:
foo_t* foo = malloc ( sizeof(foo_t) );
To make it compile as C++ you have to write:
foo_t* foo = static_cast<foo_t*>( malloc ( sizeof(foo_t) ) );
which isn't valid C any more. (you could use the C-style cast, it wh...
Using querySelectorAll to retrieve direct children
...
let myDiv = getElementById("myDiv");
myDiv.querySelectorAll(":scope > .foo");
Note that in some cases you can also skip .querySelectorAll and use other good old-fashioned DOM API features. For example, instead of myDiv.querySelectorAll(":scope > *") you could just write myDiv.children, for...
What is the difference between $(command) and `command` in shell programming?
...ommand substitution because $() can easily nest within itself as in $(echo foo$(echo bar)). There are other differences such as how backslashes are parsed in the backtick/gravemark version, etc.
See BashFAQ/082 for several reasons to always prefer the $(...) syntax.
Also see the POSIX spec for d...
How can I pretty-print JSON in a shell script?
...
With Python 2.6+ you can just do:
echo '{"foo": "lorem", "bar": "ipsum"}' | python -m json.tool
or, if the JSON is in a file, you can do:
python -m json.tool my_json.json
if the JSON is from an internet source such as an API, you can use
curl http://my_url/ | p...