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Logical operators (“and”, “or”) in DOS batch
...an implicit conjunction.
IF Exist File1.Dat IF Exist File2.Dat GOTO FILE12_EXIST_LABEL
If File1.Dat and File1.Dat exist then jump the label FILE12_EXIST_LABEL.
See also: IF /?
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How can I cast int to enum?
...ags or enum values
.field public specialname rtspecialname int32 value__
}
What should get your attention here is that the value__ is stored separately from the enum values. In the case of the enum Foo above, the type of value__ is int16. This basically means that you can store whatever you w...
ValueError: setting an array element with a sequence
...9 when building an array of objects (not necessarily lists) that implement __getitem__ as specified here:github.com/numpy/numpy/issues/5100
– dashesy
Nov 21 '14 at 19:13
add a...
Best way to merge two maps and sum the values of same key?
...leads to arguably the shortest/cleanest solution:
scala> import scalaz._
import scalaz._
scala> import Scalaz._
import Scalaz._
scala> val map1 = Map(1 -> 9 , 2 -> 20)
map1: scala.collection.immutable.Map[Int,Int] = Map(1 -> 9, 2 -> 20)
scala> val map2 = Map(1 -> 100, ...
Can I access constants in settings.py from templates in Django?
..., frequently-used settings constants to the template such as settings.MEDIA_URL and some of the language settings if you use django's built in generic views or pass in a context instance keyword argument in the render_to_response shortcut function. Here's an example of each case:
from django.short...
How to forward declare a template class in namespace std?
...served for use by the implementation, so you should use something like TEST_H instead of __TEST__. It's not going to generate a warning or an error, but if your program has a clash with an implementation-defined identifier, then it's not guaranteed to compile or run correctly: it's ill-formed. Also ...
Bash empty array expansion with `set -u`
...4.4.
$ bash --version | head -n 1
GNU bash, version 4.4.19(1)-release (x86_64-pc-linux-gnu)
$ set -u
$ arr=()
$ echo "foo: '${arr[@]}'"
foo: ''
There is a conditional you can use inline to achieve what you want in older versions: Use ${arr[@]+"${arr[@]}"} instead of "${arr[@]}".
$ function ...
What kind of leaks does automatic reference counting in Objective-C not prevent or minimize?
...chain referring back to an earlier object.
It is for this reason that the __unsafe_unretained and __weak ownership qualifiers exist. The former will not retain any object it points to, but leaves open the possibility of that object going away and it pointing to bad memory, whereas the latter doesn...
Docker - how can I copy a file from an image to a host?
...
Actually, I use docker run --rm --entrypoint tar _image_ cC _img_directory_ . | tar xvC _host_directory_
– caligari
Nov 30 '17 at 11:04
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Python dictionary from an object's fields
...s'. To build a dictionary from an arbitrary object, it's sufficient to use __dict__. Usually, you'll declare your methods at class level and your attributes at instance level, so __dict__ should be fine. For example:
>>> class A(object):
... def __init__(self):
... self.b = 1
... ...