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Java: Instanceof and Generics
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The error message says it all. At runtime, the type is gone, there is no way to check for it.
You could catch it by making a factory for your object like this:
public static <T> MyObject<T> createMyObject(Class<T> type) {
retu...
Use numpy array in shared memory for multiprocessing
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To add to @unutbu's (not available anymore) and @Henry Gomersall's answers. You could use shared_arr.get_lock() to synchronize access when needed:
shared_arr = mp.Array(ctypes.c_double, N)
# ...
def f(i): # could be anything numpy accepts as an index such another numpy array
with ...
What does default(object); do in C#?
... value
For Nullable<T> it returns the empty (pseudo-null) value (actually, this is a re-statement of the first bullet, but it is worth making it explicit)
The biggest use of default(T) is in generics, and things like the Try... pattern:
bool TryGetValue(out T value) {
if(NoDataIsAvailab...
Convert a list to a data frame
...hich in turn yields FALSE as its default.
Assuming your list of lists is called l:
df <- data.frame(matrix(unlist(l), nrow=length(l), byrow=T))
The above will convert all character columns to factors, to avoid this you can add a parameter to the data.frame() call:
df <- data.frame(matrix(unl...
Why is Python 3.x's super() magic?
In Python 3.x, super() can be called without arguments:
1 Answer
1
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How to execute XPath one-liners from shell?
...uld try these tools :
xmlstarlet : can edit, select, transform... Not installed by default, xpath1
xmllint : often installed by default with libxml2-utils, xpath1 (check my wrapper to have --xpath switch on very old releases and newlines delimited output (v < 2.9.9)
xpath : installed via perl's ...
Unable to find a locale path to store translations for file __init__.py
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Actually you can configure where the locale folder is. In your settings.py add:
LOCALE_PATHS = (
PROJECT_ROOT + '/website/locale', )
Then create a folder for each of the languages you want to translate:
mkdir -p website/...
Why do some functions have underscores “__” before and after the function name?
...rms using leading or trailing underscores are
recognized (these can generally be combined with any case convention):
_single_leading_underscore: weak "internal use" indicator. E.g. from M import * does not import objects whose name starts with an underscore.
single_trailing_underscore_: ...
How to convert a Hibernate proxy to a real entity object
...e objects and some of them are loaded as proxies due to lazy loading. It's all OK and I don't want to turn lazy loading off.
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Iterating over every two elements in a list
... y in pairwise(l):
print "%d + %d = %d" % (x, y, x + y)
Or, more generally:
from itertools import izip
def grouped(iterable, n):
"s -> (s0,s1,s2,...sn-1), (sn,sn+1,sn+2,...s2n-1), (s2n,s2n+1,s2n+2,...s3n-1), ..."
return izip(*[iter(iterable)]*n)
for x, y in grouped(l, 2):
print...