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How important is the order of columns in indexes?
... Also keep in mind, suppose your Index is like the picture above, and your query filters on column1 and column2, but column2 is more unique and what you really want to filter on is actually column2, then its more beneficial to just have a index where column 2 is first. This may seem counte...
Extract month and year from a zoo::yearmon object
... "%m"))
[1] 3
> as.numeric(format(date1, "%Y"))
[1] 2012
See ?yearmon and ?strftime for details - the latter explains the placeholder characters you can use.
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What is the canonical way to check for errors using the CUDA runtime API?
Looking through the answers and comments on CUDA questions, and in the CUDA tag wiki , I see it is often suggested that the return status of every API call should checked for errors. The API documentation contains functions like cudaGetLastError , cudaPeekAtLastError , and cudaGetErrorString , b...
How do I daemonize an arbitrary script in unix?
I'd like a daemonizer that can turn an arbitrary, generic script or command into a daemon .
12 Answers
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Python SQL query string formatting
...bugging
my application I'd like to log to file all the sql query strings, and it is
important that the string is properly formated.
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Force R not to use exponential notation (e.g. e+10)?
...a grey area. You need to recall that R will always invoke a print method, and these print methods listen to some options. Including 'scipen' -- a penalty for scientific display. From help(options):
‘scipen’: integer. A penalty to be applied when deciding to print
numeric value...
Different bash prompt for different vi editing mode?
...have a prompt that depends on the mode you are currently in (insert or command). How does one find out this editing mode?
8...
How to tell if a string is not defined in a Bash shell script
...Autoconf, you'll find that they do not recommend combining terms with '-a' and do recommend using separate simple tests combined with &&. I've not encountered a system where there is a problem; that doesn't mean they didn't used to exist (but they are probably extremely rare these days, eve...
How do CDI and EJB compare? interact?
I'm having a tough time understanding how the two interact and where the boundary between them lies. Do they overlap? Are there redundancies between them?
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How does the const constructor actually work?
...calized" instance.
That is, all constant expressions begin canonicalized, and later these "canonicalized" symbols are used to recognize equivalence of these constants.
Canonicalization:
A process for converting data that has more than one possible representation into a "standard" canonical repres...