大约有 47,000 项符合查询结果（耗时：0.0493秒） [XML]
How to map and remove nil values in Ruby
...
Ruby 2.7 is introducing filter_map for this exact purpose. It's idiomatic and performant, and I'd expect it to become the norm very soon.
For example:
numbers = [1, 2, 5, 8, 10, 13]
enum.filter_map { |i| i * 2 if i.even? }
# => [4, 16, 20]
In your case, as the block evaluates to falsey, simp...
Can I bind an array to an IN() condition?
...right. fixed the code (didn't test it though)
edit: both chris (comments) and somebodyisintrouble suggested that the foreach-loop ...
(...)
// bindvalue is 1-indexed, so $k+1
foreach ($ids as $k => $id)
$stmt->bindValue(($k+1), $id);
$stmt->execute();
... might be redundant, so the...
Declaration/definition of variables locations in ObjectiveC?
Ever since starting to work on iOS apps and objective C I've been really puzzled by the different locations where one could be declaring and defining variables. On one hand we have the traditional C approach, on the other we have the new ObjectiveC directives that add OO on top of that. Could you fo...
Finding three elements in an array whose sum is closest to a given number
Given an array of integers, A 1 , A 2 , ..., A n , including negatives and positives, and another integer S. Now we need to find three different integers in the array, whose sum is closest to the given integer S. If there exists more than one solution, any of them is ok.
...
Understanding the map function
Apply function to every item of iterable and return a list of the results. If additional iterable arguments are passed, function must take that many arguments and is applied to the items from all iterables in parallel.
...
How to Create Multiple Where Clause Query Using Laravel Eloquent?
I'm using the Laravel Eloquent query builder and I have a query where I want a WHERE clause on multiple conditions. It works, but it's not elegant.
...
LINQ Aggregate algorithm explained
...
The easiest-to-understand definition of Aggregate is that it performs an operation on each element of the list taking into account the operations that have gone before. That is to say it performs the action on the first and second element and carr...
Convert int to char in java
...onding to '1')
If you want to convert a digit (0-9), you can add 48 to it and cast, or something like Character.forDigit(a, 10);.
If you want to convert an int as in ascii value, you can use Character.toChars(48) for example.
...
delete vs delete[] operators in C++
What is the difference between delete and delete[] operators in C++?
7 Answers
7
...
What is the significance of load factor in HashMap?
HashMap has two important properties: size and load factor . I went through the Java documentation and it says 0.75f is the initial load factor. But I can't find the actual use of it.
...