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undefined reference to boost::system::system_category() when compiling
...raries. I have the 1.46-dev Boost libraries from the Ubuntu Repository installed, but I get an error when compiling the program.
...
Get selected subcommand with argparse
...s:
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('-g', '--global')
>>> subparsers = parser.add_subparsers(dest="subparser_name") # this line changed
>>> foo_parser = subparsers.add_parser('foo')
>>> foo_parser.add_argument('-c', '--count...
putting current class as return type annotation [duplicate]
...e. Instead, they are preserved in __annotations__ in string form. This is called Postponed Evaluation of Annotations, introduced in PEP 563.
Also note:
Deprecation policy
Starting with Python 3.7, a __future__ import is required to use the
described functionality. No warnings are raised...
How to convert a java.util.List to a Scala list
...
import scala.collection.JavaConversions._
will do implicit conversion for you; e.g.:
var list = new java.util.ArrayList[Int](1,2,3)
list.foreach{println}
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How do I run a Ruby file in a Rails environment?
...------
#!/usr/bin/env /Users/me/rails_project/script/rails runner
Product.all.each { |p| p.price *= 2 ; p.save! }
-------------------------------------------------------------
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How to check if a value exists in a dictionary (python)
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it wasn't necesarry after all, unless run on bigger dict. I guess overhead in values() is caused by copying the value list and in viewvalues() by maintaining the view alive.
– soulcheck
Nov 21 '11 at 17:12
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Relative paths in Python
..., you want to do something like this:
import os
dirname = os.path.dirname(__file__)
filename = os.path.join(dirname, 'relative/path/to/file/you/want')
This will give you the absolute path to the file you're looking for. Note that if you're using setuptools, you should probably use its package re...
How to pattern match using regular expression in Scala?
...ter match {
case Pattern(c) => c bound to capture group here
case _ =>
}
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String formatting: % vs. .format vs. string literal
...ated. And Python, not being a lazy language, evaluates expressions before calling functions, so in your log.debug example, the expression "some debug info: %s"%some_infowill first evaluate to, e.g. "some debug info: roflcopters are active", then that string will be passed to log.debug().
...
Python Threading String Arguments
...t list
processThread.start()
If you notice, from the stack trace: self.__target(*self.__args, **self.__kwargs)
The *self.__args turns your string into a list of characters, passing them to the processLine
function. If you pass it a one element list, it will pass that element as the first argum...