大约有 47,000 项符合查询结果（耗时：0.0341秒） [XML]
How to reshape data from long to wide format
...mes(df) <- unique(dat1$name)
df
sqldf package:
library(sqldf)
sqldf('SELECT name,
MAX(CASE WHEN numbers = 1 THEN value ELSE NULL END) x1,
MAX(CASE WHEN numbers = 2 THEN value ELSE NULL END) x2,
MAX(CASE WHEN numbers = 3 THEN value ELSE NULL END) x3,
MAX(CASE WHEN numbe...
How do I remove the horizontal scrollbar in a div?
...
To hide the horizontal scrollbar, we can just select the scrollbar of the required div and set it to display: none;
One thing to note is that this will only work for WebKit-based browsers (like Chrome) as there is no such option available for Mozilla.
In order to selec...
One-liner to recursively list directories in Ruby?
...elsif child.directory?
rec_path(child, file) + [child]
end
end.select { |x| x }.flatten(1)
end
# only directories
rec_path(Pathname.new(dir), false)
# directories and normal files
rec_path(Pathname.new(dir), true)
...
How do I rename a column in a database table using SQL?
...any other RDBMS), you can do it with regular ALTER TABLE statement:
=> SELECT * FROM Test1;
id | foo | bar
----+-----+-----
2 | 1 | 2
=> ALTER TABLE Test1 RENAME COLUMN foo TO baz;
ALTER TABLE
=> SELECT * FROM Test1;
id | baz | bar
----+-----+-----
2 | 1 | 2
...
App.Config Transformation for projects which are not Web Projects in Visual Studio?
...="@*|node()">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="/configuration/appSettings">
<xsl:copy>
<xsl:apply-templates select="node()|@*"/>
<xsl:element name="add"&g...
Opening project in Visual Studio fails due to nuget.targets not found error
...
Install Nuget.
Right click on the solution and select "Enable NuGet
Package Restore". In Visual Studio 2013 and later, select "Restore NuGet Packages" instead.
Click Ok on the warning.
Close and re-open the solution.
Should now be hunky-dory.
...
What's wrong with nullable columns in composite primary keys?
...ow in a table: when a table has a primary key, you have a guranteed way to select any row from it.
A unique constraint does not necessarily identify every row; it just specifies that if a row has values in its columns, then they must be unique. This is not sufficient to uniquely identify every row...
How find all unused classes in Intellij Idea?
...lick on Java/Declaration redundancy/Unused declaration
on the right bottom select "On the fly editor settings"
untick check fields, ..., check parameters. Only Check Classes should be ticked.
Press OK
Settings closes
On the menu bar, click on Analyze / Run Inspection by Name (or Ctrl+Alt+Shift+I...
Generate C# class from XML
... file as classes.
Copy your XML file's content to clipboard
In editor, select place where you want your classes to be pasted
From the menu, select EDIT > Paste Special > Paste XML As Classes
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What port is a given program using? [closed]
...ool.
In Process Explorer: locate the process in question, right-click and select the TCP/IP tab. It will even show you, for each socket, a stack trace representing the code that opened that socket.
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