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What's the fastest way to merge/join data.frames in R?
...(y) from main.d group by g1, g2"))
)
The outputs from the two benchmark call comparing the merge calculations are:
Joining by: x
test replications elapsed relative user.self sys.self user.child sys.child
3 data.table 1 0.34 1.000000 0.31 0.01 NA NA
2 ...
Converting ISO 8601-compliant String to java.util.Date
... hours off UTC, so the string does not necessarily end with ":00".
ISO8601 allows only the number of hours to be included in the time zone, so "+01" is equivalent to "+01:00"
ISO8601 allows the usage of "Z" to indicate UTC instead of "+00:00".
The easier solution is possibly to use the data type c...
read.csv warning 'EOF within quoted string' prevents complete reading of file
...ce and Inductive Confirmation\t" "Sound and Sense in Cath Almaine\t" "Oak Galls Preserved by the Eruption of Mount Vesuvius in A.D. 79_ and Their Probable Use\t" "The Arts Four Thousand Years Ago\t" ...
## $ title : chr "Bruce D. Smith\t" "Tomás Ó Cathasaigh\t" "Hiram G. Larew\t" "\t" ......
Validating IPv4 addresses with regexp
...so it ends with a word boundary rather than with the end of line? Additionally here I've marked the non-capturing groups to avoid unwanted sub-matches. NB: This still doesn't take into account @dty's comment as I'm not familiar with that form of IP; though he's correct that it seems valid.
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Simplest way to detect a mobile device in PHP
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@kavior.com Yes it can be faked, but we should allow people to fake if they wish... because that would be their intention, why stop people from doing what they specifically want (i.e. load the desktop version for some reason in particular)?
– Nick St...
What is the GAC in .NET?
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Right, so basically it's a way to keep DLLs globally accessible without worrying about conflicts. No more DLL Hell. Each architecture and version gets it's own place to live.
It also gets it own way to browse it in Explorer, so if you go...
How do I translate an ISO 8601 datetime string into a Python datetime object? [duplicate]
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I prefer using the dateutil library for timezone handling and generally solid date parsing. If you were to get an ISO 8601 string like: 2010-05-08T23:41:54.000Z you'd have a fun time parsing that with strptime, especially if you didn't know up front whether or not the timezone was included. ...
Select top 10 records for each category
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If you really just want the top 10, change it to RowNumber() instead of Rank(). No ties then.
– Mike L
Oct 7 '08 at 3:26
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Difference between timestamps with/without time zone in PostgreSQL
...rpreted.
The effects of time zones on these data types is covered specifically in the docs. The difference arises from what the system can reasonably know about the value:
With a time zone as part of the value, the value can be rendered as a local time in the client.
Without a time zone as part o...
Best way to do nested case statement logic in SQL Server
...f I want to rename 'calculation1' to 'CAL1'... How is it possible syntactically ?
– Renascent
Apr 12 '17 at 6:38
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