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Evaluate expression given as a string
...ied. For example, if you have a pre-defined variable name equal to "David" and you reassign using eval(parse(text = "name") == "Alexander", you will get an error because eval & parse do not return an R expression that can be evaluated.
– Crt
Aug 1 '16 at 22...
How do you count the number of occurrences of a certain substring in a SQL varchar?
...to mind is to do it indirectly by replacing the comma with an empty string and comparing the lengths
Declare @string varchar(1000)
Set @string = 'a,b,c,d'
select len(@string) - len(replace(@string, ',', ''))
share
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What is the tilde (~) in the enum definition?
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~ is the unary one's complement operator -- it flips the bits of its operand.
~0 = 0xFFFFFFFF = -1
in two's complement arithmetic, ~x == -x-1
the ~ operator can be found in pretty much any language that borrowed syntax from C, including Objective-C/C++/C#/Java/Javascript.
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Define make variable at rule execution time
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In your example, the TMP variable is set (and the temporary directory created) whenever the rules for out.tar are evaluated. In order to create the directory only when out.tar is actually fired, you need to move the directory creation down into the steps:
out.tar : ...
How to use > in an xargs command?
I want to find a bash command that will let me grep every file in a directory and write the output of that grep to a separate file. My guess would have been to do something like this
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How to calculate number of days between two given dates?
If I have two dates (ex. '8/18/2008' and '9/26/2008' ), what is the best way to get the number of days between these two dates?
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In a .csproj file, what is for?
... differences.
None - The file is not included in the project output group and is not compiled in the build process. An example is a text file that contains documentation, such as a Readme file.
Content - The file is not compiled, but is included in the Content output group. For example, this settin...
Detect the specific iPhone/iPod touch model [duplicate]
... game that utilizes the peer-to-peer bluetooth capabilities of the iPhone (and probably the iPod touch 2nd generation). However, to stop the users from trying to play a multiplayer on an iPod 1st gen and iPhone 2G I need to check for the specific device model.
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What is the syntax for an inner join in LINQ to SQL?
I'm writing a LINQ to SQL statement, and I'm after the standard syntax for a normal inner join with an ON clause in C#.
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Open multiple Eclipse workspaces on the Mac
...he officially supported way to do this as of 10.5. Earlier version of OS X and even 10.5 and up should still work using the following instructions though.
Open the command line (Terminal)
Navigate to your Eclipse installation folder, for instance:
cd /Applications/eclipse/
cd /Developer/Eclip...