大约有 12,000 项符合查询结果（耗时：0.0266秒） [XML]
Specialization with Constraints
...ion with a class constraint. I have a minimal example of my problem here: Foo.hs and Main.hs . The two files compile (GHC 7.6.2, ghc -O3 Main ) and run.
...
Awkward way of executing JavaScript code [duplicate]
...
var a = (function() {
return foo(bar);
})();
In this case this is really unnecessary, but this is not wrong and it will not throw an error.
But IIF some times uses like module pattern:
var a = (function() {
/* some other code in own scope */
retu...
shared_ptr指针被赋值后，原指针会引用清零、自动释放。 - C/C++ - 清泛IT...
...会引用清零、自动释放。
std::shared_ptr<int> intg;
void foo(std::shared_ptr<int> p)
{
intg = p; // 原指针释放，存储新的智能指针
//*(intg.get()) = *(p.get()); // ...
How to escape special characters in building a JSON string?
...nonsense; strings in JSON can only ever be double-quoted. Try JSON.parse("'foo'") in your browser console, for example, and observe the SyntaxError: Unexpected token '. The JSON spec is really simple and clear about this. There is no escape sequence in JSON for single quotes, and a JSON string canno...
How to remove leading and trailing whitespace in a MySQL field?
...
You're looking for TRIM.
UPDATE FOO set FIELD2 = TRIM(FIELD2);
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In-place edits with sed on OS X
...native way is to use built-in substitution in Vim Ex mode, like:
$ ex +%s/foo/bar/g -scwq file.txt
and for multiple-files:
$ ex +'bufdo!%s/foo/bar/g' -scxa *.*
To edit all files recursively you can use **/*.* if shell supports that (enable by shopt -s globstar).
Another way is to use gawk a...
Creating a singleton in Python
...
class Foo(object):
pass
some_global_variable = Foo()
Modules are imported only once, everything else is overthinking. Don't use singletons and try not to use globals.
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MySQL/SQL: Group by date only on a Datetime column
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Cast the datetime to a date, then GROUP BY using this syntax:
SELECT SUM(foo), DATE(mydate) FROM a_table GROUP BY DATE(a_table.mydate);
Or you can GROUP BY the alias as @orlandu63 suggested:
SELECT SUM(foo), DATE(mydate) DateOnly FROM a_table GROUP BY DateOnly;
Though I don't think it'll make...
How to get label of select option with jQuery?
...layed text for both styles of <option> elements:
<option label="foo"><option> -> "foo"
<option>bar<option> -> "bar"
If it has both a label attribute and text inside the element, it'll use the label attribute, which is the same behavior as the browser.
For pos...
Reference: Comparing PHP's print and echo
...equence:
<?php
function bar( $baz ) {
// other code
}
function foo() {
return print("In and out ...\n");
}
if ( foo() ) {
bar();
}
You might find print of particular value when it comes to debugging on the fly, as the next example illustrates:
<?php
$haystack = 'abcde';
$n...