大约有 40,000 项符合查询结果（耗时：0.0196秒） [XML]
How do I use shell variables in an awk script?
...f the environment variable ("${v}"):
% awk -vv="${v}" 'BEGIN { print v }'
123test
Or to make it clearer (with far fewer vs):
% environment_variable=123test
% awk -vawk_variable="${environment_variable}" 'BEGIN { print awk_variable }'
123test
...
Avoiding if statement inside a for loop?
... Library. It is called the strategy pattern.
If you are allowed to use C++11, you can do something like this:
#include <iostream>
#include <set>
#include <vector>
template <typename Container, typename Functor, typename Index = std::size_t>
void for_each_indexed(const Cont...
How to define “type disjunction” (union types)?
...s solution as follows:
sealed trait Or[A, B]
object Or {
implicit def a2Or[A,B](a: A) = new Or[A, B] {}
implicit def b2Or[A,B](b: B) = new Or[A, B] {}
}
object Bar {
def foo[T <% String Or Int](x: T) = x match {
case _: String => println("str")
case _: Int => println("...
Creating an array of objects in Java
...a = new A[4];
...creates 4 A references, similar to doing this:
A a1;
A a2;
A a3;
A a4;
Now you couldn't do a1.someMethod() without allocating a1 like this:
a1 = new A();
Similarly, with the array you need to do this:
a[0] = new A();
...before using it.
...
How to query nested objects?
...r is a subdocument that contains only the field company with the value 'ABC123' and the field address with the value '123 Street', in the exact order:
db.inventory.find( {
producer: {
company: 'ABC123',
address: '123 Street'
}
});
...
Get JSON object from URL
...#000000005f2b81c80000000076756fef> {}
>>> $q->{'qwert-y'} = 123
=> 123
>>> var_dump($q);
class stdClass#174 (1) {
public $qwert-y =>
int(123)
}
=> null
share
|
...
SQL update fields of one table from fields of another one
...('a.' || quote_ident(column_name), ',') || ')
FROM a
WHERE b.id = 123
AND a.id = b.id'
FROM information_schema.columns
WHERE table_name = 'a' -- table name, case sensitive
AND table_schema = 'public' -- schema name, case sensitive
AND column_name <> 'id' -...
Reference: mod_rewrite, URL rewriting and “pretty links” explained
...tact.html
RewriteRule ^about$ about.php
Numeric identifiers /object/123
Introducing shortcuts like http://example.com/article/531 to existing PHP scripts is also easy. The numeric placeholder can just be remapped to a $_GET parameter:
RewriteRule ^article/(\d+)$ article-show.php?id=$1
...
Xcode doesn't show the line that causes a crash
...erredBlocks + 653
12 UIKit 0x000000010ec7a273 _cleanUpAfterCAFlushAndRunDeferredBlocks + 566
13 UIKit 0x000000010ec9d757 __84-[UIApplication _handleApplicationActivationWithScene:transitionContext:completion:]_block_invoke_2 + 194...
How to change a django QueryDict to Python Dict?
...s Arrays you can do the following:
# request = <QueryDict: {u'key': [u'123ABC']}>
dict(zip(request.GET.keys(), request.GET.values()))
{u'key': u"123ABC" }
# Only work for single item lists
# request = <QueryDict: {u'key': [u'123ABC',U 'CDEF']}>
dict(zip(request.GET.keys(), request.GET....