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How to remove unused imports from Eclipse
...swered Mar 26 '13 at 6:24
niknik123niknik123
18111 silver badge77 bronze badges
...
java.util.regex - importance of Pattern.compile()?
...ch is really called a lot :)
public class AmountValidator {
//Accept 123 - 123,456 - 123,345.34
private static final String AMOUNT_REGEX="\\d{1,3}(,\\d{3})*(\\.\\d{1,4})?|\\.\\d{1,4}";
//Compile and save the pattern
private static final Pattern AMOUNT_PATTERN = Pattern.compile(AM...
Remove duplicated rows using dplyr
...ction for this purpose.
Original answer below:
library(dplyr)
set.seed(123)
df <- data.frame(
x = sample(0:1, 10, replace = T),
y = sample(0:1, 10, replace = T),
z = 1:10
)
One approach would be to group, and then only keep the first row:
df %>% group_by(x, y) %>% filter(row_nu...
Consequences of using graft in Mercurial
... account.
Q2: Is this merge just a normal 3-way merge using D, J' and M1?
A2: Yes, grafting does not alter the topology of the graph.
Q3: Has mercurial stored/used extra information about the graft operation to help it with the merge?
A3: No.
Q4: What are the potential problems with a flow like th...
sed: print only matching group
...it with a 2nd grep.
# To extract \1 from /xx([0-9]+)yy/
$ echo "aa678bb xx123yy xx4yy aa42 aa9bb" | grep -Eo 'xx[0-9]+yy' | grep -Eo '[0-9]+'
123
4
# To extract \1 from /a([0-9]+)b/
$ echo "aa678bb xx123yy xx4yy aa42 aa9bb" | grep -Eo 'a[0-9]+b' | grep -Eo '[0-9]+'
678
9
...
What is boxing and unboxing and what are the trade offs?
...xing is the conversion of a reference type into a value type.
EX: int i = 123;
object o = i;// Boxing
int j = (int)o;// UnBoxing
Value Types are: int, char and structures, enumerations.
Reference Types are:
Classes,interfaces,arrays,strings and objects
...
Dynamic SQL - EXEC(@SQL) versus EXEC SP_EXECUTESQL(@SQL)
...
EXEC('SELECT * FROM FOO WHERE ID=?', 123) will replace the parameter placeholder "?" with the value 123 and then execute the query, returning a result for SELECT * FROM FOO WHERE ID=123
– Peter Wone
Jun 1 '10 at 23:27
...
What does the explicit keyword mean?
...class type.
For example, the following statements are legal:
A a1;
A a2 = A(1);
A a3(1);
A a4 = A("Venditti");
A* p = new A(1);
A a5 = (A)1;
A a6 = static_cast<A>(1);
share
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...
How do I match any character across multiple lines in a regular expression?
...er (demo): "(?s)(.*)<Foobar>" (in Google Spreadsheets, =REGEXEXTRACT(A2,"(?s)(.*)<Foobar>"))
NOTES ON (?s):
In most non-POSIX engines, (?s) inline modifier (or embedded flag option) can be used to enforce . to match line breaks.
If placed at the start of the pattern, (?s) changes the...
ServiceStack vs ASP.Net Web API [closed]
...
Community♦
111 silver badge
answered Mar 14 '12 at 19:54
mythzmythz
131k2525 gold badges2...