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argparse module How to add option without any argument?
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As @Felix Kling suggested use action='store_true':
>>> from argparse import ArgumentParser
>>> p = ArgumentParser()
>>> _ = p.add_argument('-f', '--foo', action='store_true')
>>> args = p.parse_args()
>>> args.foo
False
&g...
How do I find the location of the executable in C? [duplicate]
...proc/self/exe points me at the unfriendly path: /home/peeterj/views/peeterj_clang-7.vws/.s/00024/8000023250b8f17fllvm-tblgen
– Peeter Joot
Nov 30 '12 at 18:23
5
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Precision String Format Specifier In Swift
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a simple way is:
import Foundation // required for String(format: _, _)
print(String(format: "hex string: %X", 123456))
print(String(format: "a float number: %.5f", 1.0321))
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impro...
JavaFX and OpenJDK
...ed application that uses JavaFX(e.g. JavaFX Scene Builder 2.0):
cp <JRE_WITH_JAVAFX_HOME>/lib/ext/jfxrt.jar <JRE_HOME>/lib/ext/
cp <JRE_WITH_JAVAFX_HOME>/lib/javafx.properties <JRE_HOME>/lib/
cp <JRE_WITH_JAVAFX_HOME>/lib/amd64/libprism_* <JRE_HOME>/lib/amd6...
How to search in array of object in mongodb
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Use $elemMatch to find the array of particular object
db.users.findOne({"_id": id},{awards: {$elemMatch: {award:'Turing Award', year:1977}}})
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Is there a goto statement in Java?
...reason to use goto that I can think of is this:
for (int i = 0; i < MAX_I; i++) {
for (int j = 0; j < MAX_J; j++) {
// do stuff
goto outsideloops; // to break out of both loops
}
}
outsideloops:
In Java you can do this like this:
loops:
for (int i = 0; i < MAX_I;...
How to create a MySQL hierarchical recursive query
...s, path IDs, or self-joins.
MySQL 8+
with recursive cte (id, name, parent_id) as (
select id,
name,
parent_id
from products
where parent_id = 19
union all
select p.id,
p.name,
p.parent_id
from products p
inn...
What is the difference between re.search and re.match?
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Now, enough talk. Time to see some example code:
# example code:
string_with_newlines = """something
someotherthing"""
import re
print re.match('some', string_with_newlines) # matches
print re.match('someother',
string_with_newlines) # won't match
print re.match('^someother', s...
When is -XAllowAmbiguousTypes appropriate?
... Foo a where
whichOne :: a -> String
instance Foo a where
whichOne _ = "a"
instance Foo [a] where
whichOne _ = "[a]"
-- |
-- >>> main
-- [a]
main :: IO ()
main = putStrLn $ whichOne (undefined :: [Int])
But GHC is not okay with overlapping instances when neither is clearly a b...
Why does installing Nokogiri on Mac OS fail with libiconv is missing?
...official solution from the Nokogiri docs (nokogiri.org/tutorials/installing_nokogiri.html#mac_os_x), and the only one that worked on El Capitan. The accepted solution did not work there.
– Johannes
Oct 17 '15 at 20:11
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