大约有 44,000 项符合查询结果（耗时：0.0618秒） [XML]
data.table vs dplyr: can one do something well the other can't or does poorly?
... ## data.table syntax
left_join(DT2, DT1) ## dplyr syntax
# 2. select columns while join
DT1[DT2, .(z, i.mul)]
left_join(select(DT2, x, y, mul), select(DT1, x, y, z))
# 3. aggregate while join
DT1[DT2, .(sum(z) * i.mul), by = .EACHI]
DF1 %>% group_by(x, y) %>% summarise(z = su...
Best way to do nested case statement logic in SQL Server
...
You could try some sort of COALESCE trick, eg:
SELECT COALESCE(
CASE WHEN condition1 THEN calculation1 ELSE NULL END,
CASE WHEN condition2 THEN calculation2 ELSE NULL END,
etc...
)
share
...
How to create EditText with rounded corners? [closed]
...g="utf-8"?>
<!-- res/drawable/rounded_edittext_states.xml -->
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:state_pressed="true"
android:state_enabled="true"
android:drawable="@drawable/rounded_focused" />
&...
Do while loop in SQL Server 2008
...ECLARE Id INT, @Title VARCHAR(50)
DECLARE Iterator CURSOR FORWARD_ONLY FOR
SELECT Id, Title FROM dbo.SourceTable
OPEN Iterator
WHILE 1=1 BEGIN
FETCH NEXT FROM @InputTable INTO @Id, @Title
IF @@FETCH_STATUS < 0 BREAK
PRINT 'Do something with ' + @Title
END
CLOSE Iterator
DEALLOCATE Ite...
Reloading/refreshing Kendo Grid
...he Kendo UI Grid based on some calls, that were happening on some dropdown selects. Here is what I ended up using:
$.ajax({
url: '/api/....',
data: { myIDSArray: javascriptArrayOfIDs },
traditional: true,
success: function(result) {
searchResults = result...
How can Xml Documentation for Web Api include documentation from beyond the main project?
...c. Add the following method below the constructor:
private XPathNavigator SelectSingleNode(string selectExpression)
{
foreach (var navigator in _documentNavigators)
{
var propertyNode = navigator.SelectSingleNode(selectExpression);
if (propertyNode != null)
retur...
Easier way to debug a Windows service
...classes.
The solution I came up with uses the Environment.Interactive the select running mode, as suggested by other answers to this post.
static void Main()
{
ServiceBase[] servicesToRun;
servicesToRun = new ServiceBase[]
{
new MyService()
};
if (Environment.UserInter...
What's the Hi/Lo algorithm?
...keys (which are then held as a range in the server & used as needed):
select NEXT from KEY_ALLOC where SEQ=?;
update KEY_ALLOC set NEXT=(old value+200) where SEQ=? and NEXT=(old value);
Providing you can commit this transaction (use retries to handle contention), you have allocated 200 keys &...
What exactly does git's “rebase --preserve-merges” do (and why?)
...her part. The differences with --preserve-merges concern which commits are selected for replay and how that replaying works for merge commits.
To be more explicit about the main differences between normal and merge-preserving rebase:
Merge-preserving rebase is willing to replay (some) merge commi...
How to get current date & time in MySQL?
...rent date in epoch format, then you can use UNIX_TIMESTAMP(). For example:
select now(3), sysdate(3), unix_timestamp();
would yield
+-------------------------+-------------------------+------------------+
| now(3) | sysdate(3) | unix_timestamp() |
+--------------------...