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Remove an entire column from a data.frame in R
... long amount of time and/or fail due to out of memory errors. Package data.table helps address this problem with the := operator:
library(data.table)
> dt <- data.table(a = 1, b = 1, c = 1)
> dt[,a:=NULL]
b c
[1,] 1 1
I should put together a bigger example to show the differences. I...
Using Panel or PlaceHolder
..., don't get me started with BrowserCaps - it can also become a single cell table in .Net 1.1 on "Downlevel" browsers.
– Zhaph - Ben Duguid
Jan 27 '09 at 13:57
6
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MIN/MAX vs ORDER BY and LIMIT
...king at an unindexed field, using MIN() requires a single full pass of the table. Using SORT and LIMIT requires a filesort. If run against a large table, there would likely be a significant difference in percieved performance. As a meaningless data point, MIN() took .36s while SORT and LIMIT took...
Switch statement fallthrough in C#?
...ere one takes a value, computes an offset from it (whether by looking up a table indexed by a perfect hash of the value, or by actual arithmetic on the value*). It's worth noting at this point that today, C# compilation will sometimes turn switch into the equivalent if-else, and sometimes use a hash...
How to vertically align elements in ?
...n, you're not worrying about IE or older browsers.
So you can use display:table-cell and display:table-row like so:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.or...
vertical-align with Bootstrap 3
... .vertical-align only on specific screen sizes like so:
/* Small devices (tablets, 768px and up) */
@media (min-width: 768px) {
.row.vertical-align {
display: flex;
align-items: center;
}
}
In that case, I'd go with @KevinNelson's approach.
Important note #2: Vendor prefi...
Check with jquery if div has overflowing elements
...
Works for most cases but won't cover up scenario with CSS tables (display table-cell, table-rwo, table) -
– Dmitry
Jul 1 '14 at 13:55
...
How to check if a function exists on a SQL database
...s for this type argument, particularly:
FN : Scalar function
IF : Inline table-valued function
TF : Table-valued-function
FS : Assembly (CLR) scalar-function
FT : Assembly (CLR) table-valued function
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How should you build your database from source control?
...sing automation - or should production by built by copying objects from a stable, finalized test environment?
Automation for both. Do NOT copy data between the environments
How do you deal with potential differences between test and production environments in deployment scripts?
Use templates, so th...
How do I perform an insert and return inserted identity with Dapper?
... is simply:
var id = connection.QuerySingle<int>( @"
INSERT INTO [MyTable] ([Stuff]) VALUES (@Stuff);
SELECT CAST(SCOPE_IDENTITY() as int)", new { Stuff = mystuff});
Note that on more recent versions of SQL Server you can use the OUTPUT clause:
var id = connection.QuerySingle<int>( @...