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Non-static variable cannot be referenced from a static context
...the class is caught by the Java compiler at compile time and flagged as an error.
import java.io.*;
class HelloWorld {
int myInt; // this is a class variable that is unique to each object
static int myInt2; // this is a class variable shared by all objects of this class
static v...
How to properly use unit-testing's assertRaises() with NoneType objects? [duplicate]
...tRaises to be use as a context manager and do:
with self.assertRaises(TypeError):
self.testListNone[:1]
If you are using python2.6 another way beside the one given until now is to use unittest2 which is a back port of unittest new feature to python2.6, and you can make it work using the code ...
proguard hell - can't find referenced class
...
This error occurs because the libs you use depend on other libs which are not realy used, but Proguard is looking for them.
Add your -dontwarn lines to your proguard-rules.pro file in your Android project to disable this warnings...
Find the min/max element of an Array in JavaScript
...rrays (~10⁷ elements), Math.min and Math.max both produces the following error in Node.js.
RangeError: Maximum call stack size exceeded
A more robust solution is to not add every element to the call stack, but to instead pass an array:
function arrayMin(arr) {
return arr.reduce(function ...
How to re-sync the Mysql DB if Master and slave have different database incase of Mysql replication?
...you should rely instead on the --master-data option to guard against human error and release the locks on the master as quickly as possible.
Assume the master is 192.168.100.50 and the slave is 192.168.100.51, each server has a distinct server-id configured, the master has binary logging on and the...
What is the difference between async.waterfall and async.series
...ction to the next, then when done will call the main callback, passing its error, if an error happens.
The difference is that async.series(), once the series have finished, will pass all the results to the main callback. async.waterfall() will pass to the main callback only the result of the last f...
Check if array is empty or null
...ery. I tried array.length === 0 but it didn't work. It did not throw any error either.
4 Answers
...
Building a minimal plugin architecture in Python
...l_plugin("example", 1234)
It's certainly "minimal", it has absolutely no error checking, probably countless security problems, it's not very flexible - but it should show you how simple a plugin system in Python can be..
You probably want to look into the imp module too, although you can do a lot...
How to validate an email address in JavaScript
... reject any valid addresses [^@]+@[^@]+\.[^@]+ and protects against common errors.
– Vroo
Oct 26 '12 at 6:32
...
What's the best way to parse command line arguments? [closed]
...
print(args.switch)
5) Check Values
if args.pos_arg > 10:
parser.error("pos_arg cannot be larger than 10")
Usage
Correct use:
$ ./app 1 2 --opt_arg 3 --switch
Argument values:
1
2
3
True
Incorrect arguments:
$ ./app foo 2 --opt_arg 3 --switch
usage: convert [-h] [--opt_arg OPT_ARG]...