大约有 11,500 项符合查询结果（耗时：0.0223秒） [XML]
What is the difference between the GNU Makefile variable assignments =, ?=, := and +=?
Can anybody give a clear explanation of how variable assignment really works in Makefiles.
6 Answers
...
How do I split a string so I can access item x?
...|8765'
Declare @individual varchar(20) = null
WHILE LEN(@products) > 0
BEGIN
IF PATINDEX('%|%', @products) > 0
BEGIN
SET @individual = SUBSTRING(@products,
0,
PATINDEX('%|%', @products))
SELECT @in...
.append(), prepend(), .after() and .before()
I am pretty proficient with coding, but now and then I come across code that seems to do basically the same thing. My main question here is, why would you use .append() rather then .after() or vice verses?
...
Convert base class to derived class [duplicate]
Is it possible in C# to explicitly convert a base class object to one of it's derived classes? Currently thinking I have to create a constructor for my derived classes that accept a base class object as a parameter and copy over the property values. I don't really like this idea, so I'd like to avoi...
Access nested dictionary items via a list of keys?
...to traverse the dictionary:
from functools import reduce # forward compatibility for Python 3
import operator
def getFromDict(dataDict, mapList):
return reduce(operator.getitem, mapList, dataDict)
and reuse getFromDict to find the location to store the value for setInDict():
def setInDict(dat...
Mysql: Select rows from a table that are not in another
How to select all rows in one table that do not appear on another?
8 Answers
8
...
How do you set, clear, and toggle a single bit?
How do you set, clear, and toggle a bit?
30 Answers
30
...
Strange, unexpected behavior (disappearing/changing values) when using Hash default value, e.g. Hash
...
First, note that this behavior applies to any default value that is subsequently mutated (e.g. hashes and strings), not just arrays.
TL;DR: Use Hash.new { |h, k| h[k] = [] } if you want the most idiomatic solution and don’t care why.
What do...
&& (AND) and || (OR) in IF statements
...
No, it will not be evaluated. And this is very useful. For example, if you need to test whether a String is not null or empty, you can write:
if (str != null && !str.isEmpty()) {
doSomethingWith(str.charAt(0));
}
or, the other w...
How to count duplicate value in an array in javascript
...
function count() {
array_elements = ["a", "b", "c", "d", "e", "a", "b", "c", "f", "g", "h", "h", "h", "e", "a"];
array_elements.sort();
var current = null;
var cnt = 0;
for (var i = 0; i < array_elements.length; i++) {
if (array_ele...