大约有 47,000 项符合查询结果（耗时：0.0368秒） [XML]
Remove columns from dataframe where ALL values are NA
...
dplyr now has a select_if verb that may be helpful here:
library(dplyr)
temp <- data.frame(x = 1:5, y = c(1,2,NA,4, 5), z = rep(NA, 5))
not_all_na <- function(x) any(!is.na(x))
not_any_na <- function(x) all(!is.na(x))
> temp
...
How to change font size in Eclipse for Java text editors?
...pect that you are changing the wrong preferences.
On the Eclipse toolbar, select Window → Preferences
Set the font size, General → Appearance → Colors and Fonts → Java → Java Editor Text Font).
Save the preferences.
Check that you do not have per-project preferences. These will override ...
Expand/collapse section in UITableView in iOS
... You could set up a cell to LOOK like a header, and setup the tableView:didSelectRowAtIndexPath to manually expand or collapse the section it is in.
I'd store an array of booleans corresponding the the "expended" value of each of your sections. Then you could have the tableView:didSelectRowAtIndexP...
Increment value in mysql update query
...ion to numbers.
To demonstrate, the following will produce the result 6:
SELECT ' 05.05 '+'.95';
String concatenation in MySQL requires the CONCAT() function so there is no ambiguity here and MySQL converts the strings to floats and adds them together.
I actually think the reason the initial q...
Filling a DataSet or DataTable from a LINQ query result set
...order.Field<DateTime>("OrderDate") > new DateTime(2001, 8, 1)
select order;
// Create a table from the query.
DataTable boundTable = query.CopyToDataTable<DataRow>();
Why won't that work for you?
share
...
How to call a stored procedure from Java and JPA
...s (
postId IN NUMBER,
commentCount OUT NUMBER )
AS
BEGIN
SELECT COUNT(*) INTO commentCount
FROM post_comment
WHERE post_id = postId;
END;
You can call it from JPA as follows:
StoredProcedureQuery query = entityManager
.createStoredProcedureQuery("count_comments"...
fatal error LNK1112: module machine type 'x64' conflicts with target machine type 'X86'
...t; Configuration Properties > Linker > Advanced > Target Machine. Select MachineX64 if you are targeting a 64 bit build, or MachineX86 if you are making a 32 bit build.
Select Build > Configuration Manager from the main menu in visual studio. Make sure your project has the correct platfo...
vim - How to delete a large block of text without counting the lines?
...ed {v}), Visual Line Mode (Line based {S-v}) and Visual Block Mode (Allows selection of blocks {C-v})
– Tom Regner
Apr 3 '11 at 18:10
|
show...
Limit file format when using ?
...te of <input type = "file"> can help to provide a filter in the file select dialog box of the OS. For example,
<!-- (IE 10+, Edge (EdgeHTML), Edge (Chromium), Chrome, Firefox 42+) -->
<input type="file" accept=".xls,.xlsx" />
should provide a way to filter out files other...
What is the use of GO in SQL Server Management Studio & Transact SQL?
...
gbn make it SELECT and look at what happens :-)
– SQLMenace
Feb 19 '10 at 21:09
14
...