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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...
Regular expression that matches valid IPv6 addresses
...ular expressions, so I wrote one that works with POSIX regular expressions and PERL regular expressions.
It should match:
IPv6 addresses
zero compressed IPv6 addresses (section 2.2 of rfc5952)
link-local IPv6 addresses with zone index (section 11 of rfc4007)
IPv4-Embedded IPv6 Address (section 2 ...
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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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...
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 JSF resource library for and how should it be used?
The JSF <h:outputStylesheet> , <h:outputScript> and <h:graphicImage> components have a library attribute. What is this and how should this be used? There are a lot of examples on the web which use it as follows with the common content/file type css , js and img (or ima...
What is a non-capturing group in regular expressions?
How are non-capturing groups, i.e. (?:) , used in regular expressions and what are they good for?
15 Answers
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How can I repeat a character in Bash?
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You can use:
printf '=%.0s' {1..100}
How this works:
Bash expands {1..100} so the command becomes:
printf '=%.0s' 1 2 3 4 ... 100
I've set printf's format to =%.0s which means that it will always print a single = no matter what argument it is given. Therefore it prints 100 =s.
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Test if characters are in a string
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@GregSnow -- Tried system.time(a <- grepl("abc", vec)) and system.time(a <- grepl("abc", vec, fixed=TRUE)), and fixed=TRUE is still, if anything slightly slower. The difference isn't appreciable with these short strings, but fixed=TRUE still doesn't seem to be faster. Thanks ...