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How do SQL EXISTS statements work?
I'm trying to learn SQL and am having a hard time understanding EXISTS statements. I came across this quote about "exists" and don't understand something:
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How to use R's ellipsis feature when writing your own function?
...nts. For example, the function data.frame takes any number of arguments, and each argument becomes the data for a column in the resulting data table. Example usage:
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Listing each branch and its last revision's date in Git
I need to delete old and unmaintained branches from our remote repository. I'm trying to find a way with which to list the remote branches by their last modified date, and I can't.
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What's the difference between --general-numeric-sort and --numeric-sort options in gnu sort
...mbers as floats, this allows scientific notation eg 1.234E10 but is slower and subject to rounding error (1.2345678 could come after 1.2345679), numeric sort is just a regular alphabetic sort that knows 10 comes after 9.
See http://www.gnu.org/software/coreutils/manual/html_node/sort-invocatio...
Why does typeof NaN return 'number'?
...eration
which return NaN:
Operations with a NaN as at least one operand
Indeterminate forms
The divisions 0/0, ∞/∞, ∞/−∞, −∞/∞, and −∞/−∞
The multiplications 0×∞ and 0×−∞
The power 1^∞
The additions ∞ + (−∞), (−∞) + ∞ and e...
Drop rows with all zeros in pandas data frame
I can use pandas dropna() functionality to remove rows with some or all columns set as NA 's. Is there an equivalent function for dropping rows with all columns having value 0?
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Hibernate, @SequenceGenerator and allocationSize
...nce by one , multiple this value by 50 (default allocationSize value) - and then uses this value as entity ID.
6 Answers...
Can't pickle when using multiprocessing Pool.map()
... is that multiprocessing must pickle things to sling them among processes, and bound methods are not picklable. The workaround (whether you consider it "easy" or not;-) is to add the infrastructure to your program to allow such methods to be pickled, registering it with the copy_reg standard librar...
What is the significance of 1/1/1753 in SQL Server?
... do they have against 1752? My great great great great great great great grandfather would be very offended.
5 Answers
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Sorting multiple keys with Unix sort
...s that need to be sorted by 1-n keys. Some of these keys might be numeric and some of them might not be. This is a fixed-width columnar file so there are no delimiters.
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