大约有 40,000 项符合查询结果（耗时：0.0748秒） [XML]
PHP memory profiling
...r example, to see how much memory my data is using, and/or which function calls are allocating the most memory.
4 Answers
...
Will strlen be calculated multiple times if used in a loop condition?
...optimiser might be able to deduce that the value won't change, but I personally wouldn't rely on that.
I'd do something like
for (int i = 0, n = strlen(ss); i < n; ++i)
or possibly
for (int i = 0; ss[i]; ++i)
as long as the string isn't going to change length during the iteration. If it mi...
Why use Ruby's attr_accessor, attr_reader and attr_writer?
...write classes which will work correctly no matter how their public API is called.
class Person
attr_accessor :age
...
end
Here, I can see that I may both read and write the age.
class Person
attr_reader :age
...
end
Here, I can see that I may only read the age. Imagine that it is set ...
Creating instance of type without default constructor in C# using reflection
...
I originally posted this answer here, but here is a reprint since this isn't the exact same question but has the same answer:
FormatterServices.GetUninitializedObject() will create an instance without calling a constructor. I found...
How to create a sequence of integers in C#?
F# has sequences that allows to create sequences:
8 Answers
8
...
ArithmeticException: “Non-terminating decimal expansion; no exact representable decimal result”
Why does the following code raise the exception shown below?
8 Answers
8
...
How do I remove duplicate items from an array in Perl?
...is as demonstrated in perlfaq4:
sub uniq {
my %seen;
grep !$seen{$_}++, @_;
}
my @array = qw(one two three two three);
my @filtered = uniq(@array);
print "@filtered\n";
Outputs:
one two three
If you want to use a module, try the uniq function from List::MoreUtils
...
How to declare a global variable in JavaScript?
...s available only in browsers. Could you edit you answer to make it work in all environments? See How to get the global object in JavaScript?
– Michał Perłakowski
Nov 30 '16 at 15:50
...
Check whether a request is GET or POST [duplicate]
...
Better use $_SERVER['REQUEST_METHOD']:
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
// …
}
share
|
improve this answer
...
How to filter array in subdocument with MongoDB [duplicate]
...use $group to put it back together:
db.test.aggregate([
{ $match: {_id: ObjectId("512e28984815cbfcb21646a7")}},
{ $unwind: '$list'},
{ $match: {'list.a': {$gt: 3}}},
{ $group: {_id: '$_id', list: {$push: '$list.a'}}}
])
outputs:
{
"result": [
{
"_id": ObjectId("512...