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To ternary or not to ternary? [closed]
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Use it for simple expressions only:
int a = (b > 10) ? c : d;
Don't chain or nest ternary operators as it hard to read and confusing:
int a = b > 10 ? c < 20 ? 50 : 80 : e == 2 ? 4 : 8;
Moreover, when using ternary operator, consider formatting th...
Check if value exists in Postgres array
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Simpler with the ANY construct:
SELECT value_variable = ANY ('{1,2,3}'::int[])
The right operand of ANY (between parentheses) can either be a set (result of a subquery, for instance) or an array. There are several ways to use it:
SQLAlchemy: how to filter on PgArray column types?
IN vs ANY op...
Numpy - add row to array
...e necessary after every row, it's much quicker to add rows in python, then convert to numpy. Here are timing tests using python 3.6 vs. numpy 1.14, adding 100 rows, one at a time:
import numpy as np
from time import perf_counter, sleep
def time_it():
# Compare performance of two methods for a...
Why was “Avoid Enums Where You Only Need Ints” removed from Android's performance tips?
The section "Avoid Enums Where You Only Need Ints" was removed from the official developer documentation . (See Why doesn't Android use more enums? for the old section content)
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Drop data frame columns by name
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the subset function works better as it won't convert a data frame with one column into a vector
– mut1na
Jun 28 '13 at 9:06
3
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Type Checking: typeof, GetType, or is?
...eritance tree.
Example
class Animal { }
class Dog : Animal { }
void PrintTypes(Animal a) {
Console.WriteLine(a.GetType() == typeof(Animal)); // false
Console.WriteLine(a is Animal); // true
Console.WriteLine(a.GetType() == typeof(Dog)); // true
Console.Wr...
overlay two images in android to set an imageview
... the canvas is drawn and the images are drawn on top of each other from point (0,0)
On button click
public void buttonMerge(View view) {
Bitmap bigImage = BitmapFactory.decodeResource(getResources(), R.drawable.img1);
Bitmap smallImage = BitmapFactory.decodeResource(getResources(...
ng-app vs. data-ng-app, what is the difference?
...follows:
Strip x- and data- from the front of the element/attributes. Convert the :, -, or _-delimited name to camelCase. Here are some equivalent
examples of elements that match ngBind:
based on above statement below all are valid directives
1. ng-bind
2. ng:bind
3. ng_bind
4. data-ng...
How to fix error “Updating Maven Project”. Unsupported IClasspathEntry kind=4?
...question in the package explorer pane, and then choosing 'Configure'-> 'Convert to Maven Project')
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What does static_assert do, and what would you use it for?
...rever, from the look of it:
class Foo
{
public:
static const int bar = 3;
};
static_assert(Foo::bar > 4, "Foo::bar is too small :(");
int main()
{
return Foo::bar;
}
$ g++ --std=c++0x a.cpp
a.cpp:7: error: static assertion failed: "Foo::bar is too small :("
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