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Select first row in each GROUP BY group?
... BY p.customer) y ON y.customer = x.customer
AND y.max_total = x.total
GROUP BY x.customer, x.total
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How do I find a “gap” in running counter with SQL?
...n a counter column in an SQL table. For example, if there are values 1,2,4 and 5 I'd like to find out 3.
20 Answers
...
How do I get the SharedPreferences from a PreferenceActivity in Android?
...er.getDefaultSharedPreferences(this);
// then you use
prefs.getBoolean("keystring", true);
Update
According to Shared Preferences | Android Developer Tutorial (Part 13) by Sai Geetha M N,
Many applications may provide a way to capture user preferences on the
settings of a specific applicati...
Prefer composition over inheritance?
...f OO design (inheritance, polymorphism, encapsulation).
class Person {
String Title;
String Name;
Int Age
}
class Employee : Person {
Int Salary;
String Title;
}
This is inheritance at work. The Employee "is a" Person or inherits from Person. All inheritance relationships are "is-...
Opening the Settings app from another app
...y Karan Dua this is now possible in iOS8 using UIApplicationOpenSettingsURLString see Apple's Documentation.
Example:
Swift 4.2
UIApplication.shared.open(URL(string: UIApplication.openSettingsURLString)!)
In Swift 3:
UIApplication.shared.open(URL(string:UIApplicationOpenSettingsURLString)!)
...
iPhone Data Usage Tracking/Monitoring
... internet.
#include <net/if.h>
#include <ifaddrs.h>
static NSString *const DataCounterKeyWWANSent = @"WWANSent";
static NSString *const DataCounterKeyWWANReceived = @"WWANReceived";
static NSString *const DataCounterKeyWiFiSent = @"WiFiSent";
static NSString *const DataCounterKeyWiFiRe...
How to get cumulative sum
... Col1,
SUM(Col1) OVER(ORDER BY RowId ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS Col2
FROM tablehh
ORDER BY RowId
or
SELECT
GroupID,
RowID,
Col1,
SUM(Col1) OVER(PARTITION BY GroupID ORDER BY RowId ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS Col2
FROM tabl...
How to model type-safe enum types?
...to get something most closely resembling a Java Enum (i.e. with sensible toString and valueOf methods -- perhaps you are persisting the enum values to a database) you need to modify it a bit. If you had used skaffman's code:
WeekDay.valueOf("Sun") //returns None
WeekDay.Tue.toString //returns We...
Appending a line to a file only if it does not already exist
...;> foo.bar
-q be quiet
-x match the whole line
-F pattern is a plain string
https://linux.die.net/man/1/grep
Edit:
incorporated @cerin and @thijs-wouters suggestions.
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When would you use a List instead of a Dictionary?
...que in dictionary.
Consider this examples:
List<KeyValuePair<int, string>> pairs = new List<KeyValuePair<int, string>>();
pairs.Add(new KeyValuePair<int, string>(1, "Miroslav"));
pairs.Add(new KeyValuePair<int, string>(2, "Naomi"));
pairs.Add(new KeyValuePair&l...