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What is the difference between ? and Object in Java generics?
...rwise, specify the types that you need:
public void printAThroughZ(Map<Character, ?> anyCharacterMap) {
for (int i = 'A'; i <= 'Z'; i++)
System.out.println(anyCharacterMap.get((char) i));
}
In the above method, we'd need to know that the Map's key is a Character, otherwise, w...
Best Practice: Access form elements by HTML id or name attribute?
... restrictions on the value of the name attribute, so e.g. you can have <select name="a+b"> or <input type="text" name="...2">, which can't be referenced using javascript .propertyName notation). Explicit [] notation also allows names built from expressions, e.g. myCheckBox = document.ge...
How do I delete multiple rows in Entity Framework (without foreach)
...Expression<Func<T, bool>> filter) where T : class
{
string selectSql = db.Set<T>().Where(filter).ToString();
string fromWhere = selectSql.Substring(selectSql.IndexOf("FROM"));
string deleteSql = "DELETE [Extent1] " + fromWhere;
db.Database.ExecuteSqlCommand(deleteSq...
How to get first character of string?
I have a string, and I need to get its first character.
16 Answers
16
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How to do a join in linq to sql with method syntax?
...eOtherClass
on sc.Property1 equals soc.Property2
select new { SomeClass = sc, SomeOtherClass = soc };
Would be equivalent to:
var result = enumerableOfSomeClass
.Join(enumerableOfSomeOtherClass,
sc => sc.Property1,
soc => soc.Property2,
...
What is the difference between square brackets and parentheses in a regex?
...nt, you would code (?:7|8|9) to make it a non capturing group.
[abc] is a "character class" that means "any character from a,b or c" (a character class may use ranges, e.g. [a-d] = [abcd])
The reason these regexes are similar is that a character class is a shorthand for an "or" (but only for singl...
How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly
... 0.0 NaN 0.0
3 0.0 1.0 2.0 3.0
4 NaN 0.0 NaN NaN
If you want to select the rows that have two or more columns with null value, you run the following:
>>> qty_of_nuls = 2
>>> df.iloc[df[(df.isnull().sum(axis=1) >=qty_of_nuls)].index]
0 1 2 3
1 0.0 NaN 0...
How do I hide an element on a click event anywhere outside of the element?
... you have other elements inside .myDiv element. For example, if you have a select dropdown inside .myDiv. When you click the select, it will think youre clicking outside the box.
– CodeGodie
Nov 22 '16 at 15:13
...
MySQL CONCAT returns NULL if any field contain NULL
...
convert the NULL values with empty string by wrapping it in COALESCE
SELECT CONCAT(COALESCE(`affiliate_name`,''),'-',COALESCE(`model`,''),'-',COALESCE(`ip`,''),'-',COALESCE(`os_type`,''),'-',COALESCE(`os_version`,'')) AS device_name
FROM devices
...
Get PostGIS version
...s like GEOS and proj4 you might want to get their versions too. Then use:
SELECT PostGIS_full_version();
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