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String concatenation vs. string substitution in Python
...e interpolation/templating.
>>> import timeit
>>> def so_q_sub(n):
... return "%s%s/%d" % (DOMAIN, QUESTIONS, n)
...
>>> so_q_sub(1000)
'http://stackoverflow.com/questions/1000'
>>> def so_q_cat(n):
... return DOMAIN + QUESTIONS + '/' + str(n)
...
>>> ...
correct way to define class variables in Python [duplicate]
...hey are just two different kinds of class elements:
Elements outside the __init__ method are static elements; they belong to the class.
Elements inside the __init__ method are elements of the object (self); they don't belong to the class.
You'll see it more clearly with some code:
class MyClass...
Get last result in interactive Python shell
...
Underscore.
>>> 5+5
10
>>> _
10
>>> _ + 5
15
>>> _
15
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Xcode doesn't show the line that causes a crash
...rminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSSingleObjectArrayI objectAtIndex:]: index 1 beyond bounds [0 .. 0]'
*** First throw call stack:
(
0 CoreFoundation 0x000000010e85cd4b __exceptionPreprocess + 171
1 libobjc.A.dylib ...
Principal component analysis in Python
...is 2 x 20. Dropping the primes,
d . Vt 2 principal vars = p.vars_pc( 20 vars )
U 1000 obs = p.pc_obs( 2 principal vars )
U . d . Vt 1000 obs, p.obs( 20 vars ) = pc_obs( vars_pc( vars ))
fast approximate A . vars, using the `npc` principal components
Ut ...
Convert a String In C++ To Upper Case
...pp>
#include <string>
std::string str = "Hello World";
boost::to_upper(str);
std::string newstr = boost::to_upper_copy<std::string>("Hello World");
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How to merge lists into a list of tuples?
...
In Python 2:
>>> list_a = [1, 2, 3, 4]
>>> list_b = [5, 6, 7, 8]
>>> zip(list_a, list_b)
[(1, 5), (2, 6), (3, 7), (4, 8)]
In Python 3:
>>> list_a = [1, 2, 3, 4]
>>> list_b = [5, 6, 7, 8]
>>> list(zi...
How to get everything after a certain character?
...then substr grabs everything from that index plus 1, onwards.
$data = "123_String";
$whatIWant = substr($data, strpos($data, "_") + 1);
echo $whatIWant;
If you also want to check if the underscore character (_) exists in your string before trying to get it, you can use the following:
i...
Average of 3 long integers
...ng divide by constants technique from hacker's delight
public class int128_t {
private int H;
private long L;
public int128_t(int h, long l)
{
H = h;
L = l;
}
public int128_t add(int128_t a)
{
int128_t s;
s.L = L + a.L;
s.H = H +...
lodash multi-column sortBy descending
...ash 3.5.0 you can use sortByOrder (renamed orderBy in v4.3.0):
var data = _.sortByOrder(array_of_objects, ['type','name'], [true, false]);
Since version 3.10.0 you can even use standard semantics for ordering (asc, desc):
var data = _.sortByOrder(array_of_objects, ['type','name'], ['asc', 'desc'...