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Rearrange columns using cut
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perlrun (1) claims -a implicitly sets -n but if I run without -n set, it doesn't seem to loop. odd.
– Trenton
Jun 9 '16 at 16:31
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What is the best way to get all the divisors of a number?
... primes = list(factors.keys())
# generates factors from primes[k:] subset
def generate(k):
if k == len(primes):
yield 1
else:
rest = generate(k+1)
prime = primes[k]
for factor in rest:
prime_to_i = 1
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Convert floating point number to a certain precision, and then copy to string
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To set precision with 9 digits, get:
print "%.9f" % numvar
Return precision with 2 digits:
print "%.2f" % numvar
Return precision with 2 digits and float converted value:
numvar = 4.2345
print float("%.2f" % numvar)
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Are list-comprehensions and functional functions faster than “for loops”?
...ases using a lambda (or other Python function), the overhead of repeatedly setting up Python stack frames etc. eats up any savings. Simply doing the same work in-line, without function calls (e.g. a list comprehension instead of map or filter) is often slightly faster.
Suppose that in a game tha...
Difference between sh and bash
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sh: http://man.cx/sh
bash: http://man.cx/bash
TL;DR: bash is a superset of sh with a more elegant syntax and more functionality. It is safe to use a bash shebang line in almost all cases as it's quite ubiquitous on modern platforms.
NB: in some environments, sh is bash. Check sh --version.
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What are paramorphisms?
... editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
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Generating v5 UUID. What is name and namespace?
...NameSpace_URL: {6ba7b811-9dad-11d1-80b4-00c04fd430c8}
NameSpace_OID: {6ba7b812-9dad-11d1-80b4-00c04fd430c8}
NameSpace_X500:{6ba7b814-9dad-11d1-80b4-00c04fd430c8}
So, you could hash together:
StackOverflowDnsUUID = sha1(Namespace_DNS + "stackoverflow.com");
StackOverflowUrlUUID = sha1(Namespace_URL ...
What is the fastest factorial function in JavaScript? [closed]
Looking for a really fast implementation of factorial function in JavaScript. Any suggests?
49 Answers
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sed beginner: changing all occurrences in a folder
...# overwrite: copy standard input to output after EOF
# (final version)
# set -x
case $# in
0|1) echo 'Usage: overwrite file cmd [args]' 1>&2; exit 2
esac
file=$1; shift
new=/tmp/$$.new; old=/tmp/$$.old
trap 'rm -f $new; exit 1' 1 2 15 # clean up files
if "$@" >$new ...
What are all the uses of an underscore in Scala?
... 0__:
trait PlaceholderExample {
def process[A](f: A => Unit)
val set: Set[_ => Unit]
set.foreach(process _) // Error
set.foreach(process(_)) // No Error
}
In the first case, process _ represents a method; Scala takes the polymorphic method and attempts to make it monomorphic by ...