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Python None comparison: should I use “is” or ==?
My editor warns me when I compare my_var == None , but no warning when I use my_var is None .
3 Answers
...
What is the definition of “interface” in object oriented programming
...dom.randint(0,10)
# What you care about
class SecretGame(object):
def __init__(self, number_generator):
number = number_generator.generate()
print number
Here, none of the classes implement an interface. Python does not care about that, because the SecretGame class will just t...
Convert Python dictionary to JSON array
...
If you are fine with non-printable symbols in your json, then add ensure_ascii=False to dumps call.
>>> json.dumps(your_data, ensure_ascii=False)
If ensure_ascii is false, then the return value will be a
unicode instance subject to normal Python str to unicode
coercion rules in...
Memoization in Haskell?
...alling, for example: fix f 123 = 144
We could memoize this by defining:
f_list :: [Int]
f_list = map (f faster_f) [0..]
faster_f :: Int -> Int
faster_f n = f_list !! n
That performs passably well, and replaces what was going to take O(n^3) time with something that memoizes the intermediate r...
Plot two histograms on single chart with matplotlib
...dom
import numpy
from matplotlib import pyplot
x = [random.gauss(3,1) for _ in range(400)]
y = [random.gauss(4,2) for _ in range(400)]
bins = numpy.linspace(-10, 10, 100)
pyplot.hist(x, bins, alpha=0.5, label='x')
pyplot.hist(y, bins, alpha=0.5, label='y')
pyplot.legend(loc='upper right')
pyplot....
sizeof single struct member in C
...ic way to do it, another would be to use a macro like this:
#define member_size(type, member) sizeof(((type *)0)->member)
and use it like this:
typedef struct
{
float calc;
char text[255];
int used;
} Parent;
typedef struct
{
char flag;
char text[member_size(Parent, text)...
How to get position of a certain element in strings vector, to use it as an index in ints vector?
...nting to the element, simply subtract v.begin() from the iterator:
ptrdiff_t pos = find(Names.begin(), Names.end(), old_name_) - Names.begin();
Now you need to check pos against Names.size() to see if it is out of bounds or not:
if(pos >= Names.size()) {
//old_name_ not found
}
vector i...
Get the value of an instance variable given its name
...
The most idiomatic way to achieve this is:
some_object.instance_variable_get("@#{name}")
There is no need to use + or intern; Ruby will handle this just fine. However, if you find yourself reaching into another object and pulling out its ivar, there's a reasonably good ...
Android Gallery on Android 4.4 (KitKat) returns different URI for Intent.ACTION_GET_CONTENT
Before KitKat (or before the new Gallery) the Intent.ACTION_GET_CONTENT returned a URI like this
19 Answers
...
How do I set a textbox's text to bold at run time?
... RegisterEvents();
}
private void RegisterEvents()
{
_tboTest.TextChanged += new EventHandler(TboTest_TextChanged);
}
private void TboTest_TextChanged(object sender, EventArgs e)
{
// Change the text to bold on specified condition
if (_tboTest.Text....