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What's the difference between using CGFloat and float?
I tend to use CGFloat all over the place, but I wonder if I get a senseless "performance hit" with this. CGFloat seems to be something "heavier" than float, right? At which points should I use CGFloat, and what makes really the difference?
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PDO Prepared Inserts multiple rows in single query
... table (fielda, fieldb, ... ) values (?,?...), (?,?...)....
That is basically how we want the insert statement to look like.
Now, the code:
function placeholders($text, $count=0, $separator=","){
$result = array();
if($count > 0){
for($x=0; $x<$count; $x++){
$re...
Pandas - How to flatten a hierarchical index in columns
..., but leaves behind column names which are difficult to access programmatically and are not queriable
– dmeu
Jun 29 '17 at 8:53
1
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How to turn on/off ReactJS 'development mode'?
...me helpers off during production. Just using the minified react will leave all those potential optimizations on the table as well.
Ultimately the magic comes down to React embedding references to process.env.NODE_ENV throughout the codebase; these act like a feature toggle.
if (process.env.NODE_ENV ...
Event system in Python
...r methods', which is a
simple implementation of the Observer pattern.
Basically, the handler methods (callables) are stored in an array and are each called when the event 'fires'.
Publish-Subscribe
The disadvantage of Observer event systems is that you can only register the handlers on the actual Ev...
How can I check for Python version in a program that uses new language features?
...rom the question that needed addressing is that a program must be syntactically correct for that version of python to even begin executing, so using new syntax precludes a program from starting on older versions of the interpreter. eval works around that
– Autoplectic
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mysql -> insert into tbl (select from another table) and some default values [duplicate]
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If you want to insert all the columns then
insert into def select * from abc;
here the number of columns in def should be equal to abc.
if you want to insert the subsets of columns then
insert into def (col1,col2, col3 ) select scol1,scol2,...
Test if a variable is a list or tuple
... excludes custom sequences, iterators, and other things that you might actually need. However, sometimes you need to behave differently if someone, for instance, passes a string. My preference there would be to explicitly check for str or unicode like so:
import types
isinstance(var, types.String...
Wrap a delegate in an IEqualityComparer
...fying. But I still don't understand your hashing policy of t => 0. If all objects always hash to the same thing (zero), then isn't that even more broken than using obj.GetHashCode, per @Dan Tao's point? Why not always force the caller to provide a good hash function?
– Jo...
What is the difference between 'my' and 'our' in Perl?
...
On the other hand, our variables are package variables, and thus automatically:
global variables
definitely not private
not necessarily new
can be accessed outside the package (or lexical scope) with the
qualified namespace, as $package_name::variable.
Declaring a variable with our allows you...