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The constant cannot be marked static
... field to store the price of a service, a product version number, or the brand name of a company. These values can change over time, and because compilers propagate constants, other code compiled with your libraries will have to be recompiled to see the changes.
From DotNetPerls:
DLLs. When yo...
Why does the expression 0 < 0 == 0 return False in Python?
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I believe Python has special case handling for sequences of relational operators to make range comparisons easy to express. It's much nicer to be able to say 0 < x <= 5 than to say (0 < x) and (x <= 5).
These are called chained comparisons. And th...
Iterate over model instance field names and values in template
...ts have changed slightly. A migration guide has been provided to assist in converting your code to use the new, official API.
In the below example, we will utilize the formalized method for retrieving all field instances of a model via Client._meta.get_fields():
fields = [(f.verbose_name, f.name) f...
JavaScript checking for null vs. undefined and difference between == and ===
...perands are of different types, === will always return false while == will convert one or both operands into the same type using rules that lead to some slightly unintuitive behaviour. If the operands are of the same type (e.g. both are strings, such as in the typeof comparison above), == and === wi...
How to check internet access on Android? InetAddress never times out
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- can't run on the UI thread
This works very reliably, on every device, and is very fast. It needs to run in a separate task though (e.g. ScheduledExecutorService or AsyncTask).
Possible Questions
Is it really fast enough?
Yes, very fast ;-)
Is there no reliable way to check internet, other t...
Python string.join(list) on object array rather than string array
...on thing in the universe: join("sep", list) - and all elements of list get converted to their string representations. I've been really struggling to find a solution in python.
– Jason
Feb 23 '18 at 13:12
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Running bash script from within python
... subprocess.check_call("./script.sh '%s'" % arg, shell=True)
Remember to convert the args to string before passing, using str(arg).
This can be used to pass as many arguments as desired:
subprocess.check_call("./script.ksh %s %s %s" % (arg1, str(arg2), arg3), shell=True)
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Change private static final field using Java reflection
...nting you from doing this, you can use setAccessible to get around private and resetting the modifier to get rid of final, and actually modify a private static final field.
Here's an example:
import java.lang.reflect.*;
public class EverythingIsTrue {
static void setFinalStatic(Field field, Obje...
How to concatenate two IEnumerable into a new IEnumerable?
...erator will attempt to use the two passed-in enumerable items (call them A and B) in sequence. If the passed-in enumerables represent sequences which will not change during the lifetime of Cat, and which can be read from without side-effects, then Cat may be used directly. Otherwise, it may be a g...
Select N random elements from a List in C#
I need a quick algorithm to select 5 random elements from a generic list. For example, I'd like to get 5 random elements from a List<string> .
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