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PHP: How to use array_filter() to filter array keys?
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PHP 5.6 introduced a third parameter to array_filter(), flag, that you can set to ARRAY_FILTER_USE_KEY to filter by key instead of value:
$my_array = ['foo' => 1, 'hello' => 'world'];
$allowed = ['foo', 'bar'];
$filte...
Reset C int array to zero : the fastest way?
...imized by hand.
memset(myarray, 0, sizeof(myarray)); // for automatically-allocated arrays
memset(myarray, 0, N*sizeof(*myarray)); // for heap-allocated arrays, where N is the number of elements
By the way, in C++ the idiomatic way would be to use std::fill (from <algorithm>):
std::fill(...
How to force a web browser NOT to cache images
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I use PHP's file modified time function, for example:
echo <img src='Images/image.png?" . filemtime('Images/image.png') . "' />";
If you change the image then the new image is used rather than the cached one, due to havi...
How to resize superview to fit all subviews with autolayout?
...ad];
// INIT ALL REQUIRED UI ELEMENTS
self.contentView = [[UIView alloc] init];
self.myLabel = [[UILabel alloc] init];
self.myOtherLabel = [[UILabel alloc] init];
NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings(_contentView, _myLabel, _myOtherLabel);
// TURN ...
What are inline namespaces for?
...impl; // implementation class
template <class T> // e.g. w/o allocator argument
class vector : __vector_impl<T> { // private inheritance
// ...
};
}
#if __cplusplus >= 1997L // C++98/03 or later
// (ifdef'ed out b/c it p...
Accessing JPEG EXIF rotation data in JavaScript on the client side
...You could have an API that takes a file URL and returns you the EXIF data; PHP has a module for that.
This could be done using Ajax so it would be seamless to the user. If you don't care about cross-browser compatibility, and can rely on HTML5 file functionality, look into the library JsJPEGmeta t...
What is the best way to test for an empty string in Go?
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TrimSpace will allocate and copy a new string from the original string, so this approach will introduce inefficiencies at scale.
– Dai
Apr 20 '18 at 1:16
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How do I determine the size of an object in Python?
...the minimum size of the following objects, and note that sets and dicts preallocate space so empty ones don't grow again until after a set amount (which may vary by implementation of the language):
Python 3:
Empty
Bytes type scaling notes
28 int +4 bytes about every 30 powers of ...
If strings are immutable in .NET, then why does Substring take O(n) time?
...nal with only a small amount (typically O(1) or O(lg n)) of copying or new allocation is called a "persistent" immutable data structure. Strings in .NET are immutable; your question is essentially "why are they not persistent"?
Because when you look at operations that are typically done on strings ...
PHP validation/regex for URL
...references to some flags have been removed entirely. More info here: news.php.net/php.internals/99018
– S. Imp
May 12 '17 at 21:53
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