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Create singleton using GCD's dispatch_once in Objective-C
...er here: instancetype
+ (instancetype)sharedInstance
{
static dispatch_once_t once;
static id sharedInstance;
dispatch_once(&once, ^
{
sharedInstance = [self new];
});
return sharedInstance;
}
+ (Class*)sharedInstance
{
static dispatch_once_t once;
...
Center HTML Input Text Field Placeholder
...
input{
text-align:center;
}
is all you need.
Working example in FF6. This method doesn't seem to be cross-browser compatible.
Your previous CSS was attempting to center the text of an input element which had a class of "placeholder".
...
Real world use cases of bitwise operators [closed]
...checksums, parity, stop bits, flow control algorithms, and so on, which usually depend on the logic values of individual bytes as opposed to numeric values, since the medium may only be capable of transmitting one bit at a time.
Compression, Encryption
Both of these are heavily dependent on bitwise ...
Convert tuple to list and back
...t is the homogeneous multidimensional array. It is a table of elements (usually numbers), all of the same type, indexed by a tuple of positive integers.
– pradyunsg
Dec 4 '16 at 3:25
...
List directory in Go
... of everything in the current directory (folders are included but not specially marked - you can check if an item is a folder by using the IsDir() method):
package main
import (
"fmt"
"io/ioutil"
"log"
)
func main() {
files, err := ioutil.ReadDir("./")
if err != nil {
...
Iterating over all the keys of a map
Is there a way to get a list of all the keys in a Go language map? The number of elements is given by len() , but if I have a map like:
...
Splitting string into multiple rows in Oracle
...ct 108 Name, 'test' Project, 'Err1, Err2, Err3' Error from dual
union all
select 109, 'test2', 'Err1' from dual
)
select distinct
t.name, t.project,
trim(regexp_substr(t.error, '[^,]+', 1, levels.column_value)) as error
from
temp t,
table(cast(multiset(select level from dual conne...
Android Notification Sound
...n Codeding
String en_alert, th_alert, en_title, th_title, id;
int noti_all, noti_1, noti_2, noti_3, noti_4 = 0, Langage;
class method
Intent intent = new Intent(context, ReserveStatusActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);
Notificati...
How do I pass a method as a parameter in Python
...thodToRun()
return result
obj.method2(obj.method1)
Note: I believe a __call__() method does exist, i.e. you could technically do methodToRun.__call__(), but you probably should never do so explicitly. __call__() is meant to be implemented, not to be invoked from your own code.
If you wanted me...
Apply multiple functions to multiple groupby columns
...ion.
I recommend making a single custom function that returns a Series of all the aggregations. Use the Series index as labels for the new columns:
def f(x):
d = {}
d['a_sum'] = x['a'].sum()
d['a_max'] = x['a'].max()
d['b_mean'] = x['b'].mean()
d['c_d_prodsum'] = (x['c'] * x['d...