大约有 46,000 项符合查询结果（耗时：0.0437秒） [XML]
Null vs. False vs. 0 in PHP
...m told that good developers can spot/utilize the difference between Null and False and 0 and all the other good "nothing" entities.
What is the difference, specifically in PHP? Does it have something to do with === ?
...
UIButton: how to center an image and a text using imageEdgeInsets and titleEdgeInsets?
If I put only an image in a button and set the imageEdgeInsets more close to the top, the image stays centered and all works as expected:
...
Drop rows with all zeros in pandas data frame
I can use pandas dropna() functionality to remove rows with some or all columns set as NA 's. Is there an equivalent function for dropping rows with all columns having value 0?
...
What is the easiest way to remove the first character from a string?
...
p asdf
# >> "12,23,987,43"
I'm always looking for the fastest and most readable way of doing things:
require 'benchmark'
N = 1_000_000
puts RUBY_VERSION
STR = "[12,23,987,43"
Benchmark.bm(7) do |b|
b.report('[0]') { N.times { "[12,23,987,43"[0] = '' } }
b.report('sub') { N.time...
Why is XOR the default way to combine hashes?
Say you have two hashes H(A) and H(B) and you want to combine them. I've read that a good way to combine two hashes is to XOR them, e.g. XOR( H(A), H(B) ) .
...
“CASE” statement within “WHERE” clause in SQL Server 2008
...tatements like this:
WHERE (
(LEN('TestPerson') = 0
AND co.personentered = co.personentered
)
OR
(LEN('TestPerson') <> 0
AND co.personentered LIKE '%TestPerson')
)
Although, either way I'm not sure how great of a query plan...
Sorting 1 million 8-decimal-digit numbers with 1 MB of RAM
I have a computer with 1 MB of RAM and no other local storage. I must use it to accept 1 million 8-digit decimal numbers over a TCP connection, sort them, and then send the sorted list out over another TCP connection.
...
What is the difference between quiet NaN and signaling NaN?
I have read about floating-point and I understand that NaN could result from operations. But I can't understand what these are concepts exactly. What is the difference between them?
...
How do I efficiently iterate over each entry in a Java Map?
If I have an object implementing the Map interface in Java and I wish to iterate over every pair contained within it, what is the most efficient way of going through the map?
...
How can I sort arrays and data in PHP?
... sorts low-to-high or reverse ("r"), whether it sorts values or keys ("k") and how it compares values ("nat" vs. normal). See http://php.net/manual/en/array.sorting.php for an overview and links to further details.
Multi dimensional arrays, including arrays of objects
$array = array(
array('foo'...