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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...
Could not load file or assembly 'System.Web.Mvc'
...
In VS2010, right click the project in the Solution Explorer and select 'Add Deployable Dependencies'. Then check the MVC related check boxes in the following dialog.
This creates a '_bin_deployableAssemblies' folder in the project which contains all the .dll files mentioned in other answ...
What's the difference between TRUNCATE and DELETE in SQL
...tranTest | DELETE FROM tranTest |
| SELECT * FROM tranTest | SELECT * FROM tranTest |
| ROLLBACK | ROLLBACK |
| SELECT * FROM tranTest | SELE...
Asp.net - Add blank item at top of dropdownlist
...drpList.Items.Insert(0, new ListItem(String.Empty, String.Empty));
drpList.SelectedIndex = 0;
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MySQL dump by query
...
not mysqldump, but mysql cli...
mysql -e "select * from myTable" -u myuser -pxxxxxxxxx mydatabase
you can redirect it out to a file if you want :
mysql -e "select * from myTable" -u myuser -pxxxxxxxx mydatabase > mydumpfile.txt
Update:
Original post asked if...
Sequelize Unknown column '*.createdAt' in 'field list'
... do not contain a timestamp column.
When you do user.find it will just do SELECT user.*, which only takes the columns you actually have. But when you join, each column of the joined table will be aliased, which creates the following query:
SELECT `users`.*, `userDetails`.`userId` AS `userDetails.u...
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...
Best way to work with transactions in MS SQL Server Management Studio
...FROM Production.Product
WHERE ProductID = 980;
END TRY
BEGIN CATCH
SELECT
ERROR_NUMBER() AS ErrorNumber
,ERROR_SEVERITY() AS ErrorSeverity
,ERROR_STATE() AS ErrorState
,ERROR_PROCEDURE() AS ErrorProcedure
,ERROR_LINE() AS ErrorLine
,ERROR_MESS...
Distinct by property of class with LINQ [duplicate]
...p:
List<Car> distinct =
cars
.GroupBy(car => car.CarCode)
.Select(g => g.First())
.ToList();
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jQuery Validate Plugin - Trigger validation of single field
...he API:
var validator = $( "#myform" ).validate();
validator.element( "#myselect" );
.valid() validates the entire form, as others have pointed out. The API says:
Checks whether the selected form is valid or whether all selected
elements are valid.
...