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NullPointerException in Java with no StackTrace
... a NullPointerException , but when I try to log the StackTrace (which basically ends up calling Throwable.printStackTrace() ), all I get is:
...
Can you attach a UIGestureRecognizer to multiple views?
... was attached before that by this recognizer is getting unattached automatically UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(didPressed:)]; [self.view1 addGestureRecognizer:tapRecognizer]; [self.view2 addGestureRecognizer:tapRecogni...
How to overcome “datetime.datetime not JSON serializable”?
...mples). The code ends by raising an exception, to deal with the case it is called with a non-serializable type.
This json_serial function can be used as follows:
from datetime import datetime
from json import dumps
print dumps(datetime.now(), default=json_serial)
The details about how the defau...
Add all files to a commit except a single file?
I have a bunch of files in a changeset, but I want to specifically ignore a single modified file. Looks like this after git status :
...
What is the 'pythonic' equivalent to the 'fold' function from functional programming?
...ression, we can use a list comprehension to replicate what other languages call fold/foldleft/reduce operations:
Given a list, a reducing function and an accumulator:
items = [1, 2, 3, 4, 5]
f = lambda acc, x: acc * x
accumulator = 1
we can fold items with f in order to obtain the resulting accu...
When to use LinkedList over ArrayList in Java?
...lements it with a doubly-linked list. ArrayList implements it with a dynamically re-sizing array.
As with standard linked list and array operations, the various methods will have different algorithmic runtimes.
For LinkedList<E>
get(int index) is O(n) (with n/4 steps on average), but O(1) ...
converting a base 64 string to an image and saving it
...appening save the image before disposing the memory stream (while still inside the using statement).
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How can I measure the actual memory usage of an application or process?
...ding if pages are shared, for example by several threads or by using dynamically linked libraries
If you really want to know what amount of memory your application actually uses, you need to run it within a profiler. For example, Valgrind can give you insights about the amount of memory used, and,...
Bash array with spaces in elements
... through its indices, like so, it works if I add the elements either numerically or with escapes:
for ((i = 0; i < ${#FILES[@]}; i++))
do
echo "${FILES[$i]}"
done
Any of these declarations of $FILES should work:
FILES=(2011-09-04\ 21.43.02.jpg
2011-09-05\ 10.23.14.jpg
2011-09-09\ 12.31.16...
Collection was modified; enumeration operation may not execute
...in subscribers.Values.ToList())
If I'm right, the problem will disappear.
Calling subscribers.Values.ToList() copies the values of subscribers.Values to a separate list at the start of the foreach. Nothing else has access to this list (it doesn't even have a variable name!), so nothing can modify i...