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How many GCC optimization levels are there?
...lear on the man page.
We shall conclude that:
anything above -O3 up to INT_MAX is the same as -O3, but that could easily change in the future, so don't rely on it.
GCC 5.1 runs undefined behavior if you enter integers larger than INT_MAX.
the argument can only have digits, or it fails gracefully. I...
Should I use a class or dictionary?
...vantage? What happens if you later want to add some code? Where would your __init__ code go?
Classes are for bundling related data (and usually code).
Dictionaries are for storing key-value relationships, where usually the keys are all of the same type, and all the values are also of one type. Occ...
Are list-comprehensions and functional functions faster than “for loops”?
...(<the code object for `[x for x in range(10)]`>)
1 0 BUILD_LIST 0
3 LOAD_FAST 0 (.0)
>> 6 FOR_ITER 12 (to 21)
9 STORE_FAST 1 (x)
12 LOAD_FAST 1 (x)
...
How do I avoid capturing self in blocks when implementing an API?
... If you're not using Automatic Reference Counting (ARC), you can do this:
__block MyDataProcessor *dp = self;
self.progressBlock = ^(CGFloat percentComplete) {
[dp.delegate myAPI:dp isProcessingWithProgress:percentComplete];
}
The __block keyword marks variables that can be modified inside th...
What is the difference between join and merge in Pandas?
...andas as pd
left = pd.DataFrame({'key': ['foo', 'bar'], 'val': [1, 2]}).set_index('key')
right = pd.DataFrame({'key': ['foo', 'bar'], 'val': [4, 5]}).set_index('key')
left.join(right, lsuffix='_l', rsuffix='_r')
val_l val_r
key
foo 1 4
bar 2 5
The same functi...
Is it intended by the C++ standards committee that in C++11 unordered_map destroys what it inserts?
...lost three days of my life tracking down a very strange bug where unordered_map::insert() destroys the variable you insert. This highly non-obvious behaviour occurs in very recent compilers only: I found that clang 3.2-3.4 and GCC 4.8 are the only compilers to demonstrate this "feature".
...
What is the purpose of Flask's context stacks?
...ing" example:
from werkzeug.wsgi import DispatcherMiddleware
from frontend_app import application as frontend
from backend_app import application as backend
application = DispatcherMiddleware(frontend, {
'/backend': backend
})
Notice that there are two completely different Flask applicat...
Split views.py in several files
...everything is a Python module (*.py). You can create a view folder with an __init__.py inside and you still will be able to import your views, because this also implements a Python module. But an example would be better.
Your original views.py might look like this :
def view1(arg):
pass
def v...
How to show all shared libraries used by executables in Linux?
... will look something like this:
1 /lib64/libexpat.so.0
1 /lib64/libgcc_s.so.1
1 /lib64/libnsl.so.1
1 /lib64/libpcre.so.0
1 /lib64/libproc-3.2.7.so
1 /usr/lib64/libbeecrypt.so.6
1 /usr/lib64/libbz2.so.1
1 /usr/lib64/libelf.so.1
1 /usr/lib64/libpopt.so.0
1 /usr/lib64/librpm-4.4.so...
Call static method with reflection
...
I prefer simplicity...
private void _InvokeNamespaceClassesStaticMethod(string namespaceName, string methodName, params object[] parameters) {
foreach(var _a in AppDomain.CurrentDomain.GetAssemblies()) {
foreach(var _t in _a.GetTypes()) {
...