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How to find and return a duplicate value in array
...irst option being the fastest:
ary = ["A", "B", "C", "B", "A"]
ary.group_by{ |e| e }.select { |k, v| v.size > 1 }.map(&:first)
ary.sort.chunk{ |e| e }.select { |e, chunk| chunk.size > 1 }.map(&:first)
And a O(N^2) option (i.e. less efficient):
ary.select{ |e| ary.count(e) > 1 ...
How to filter Android logcat by application? [duplicate]
How can I filter Android logcat output by application? I need this because when I attach a device, I can't find the output I want due to spam from other processes.
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Sorting arrays in NumPy by column
How can I sort an array in NumPy by the nth column?
13 Answers
13
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Linear Regression and group by in R
...to a vector. That does not seem very R-like, however. In SAS I would do a 'by' statement and in SQL I would do a 'group by'. What's the R way of doing this?
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Local Storage vs Cookies
I want to reduce load times on my websites by moving all cookies into local storage since they seem to have the same functionality. Are there any pros/cons (especially performance-wise) in using local storage to replace cookie functionality except for the obvious compatibility issues?
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Get JSF managed bean by name in any Servlet related class
...vlet (for AJAX/JSON) in which I would like to reference my @ManagedBeans by name. I'm hoping to map:
6 Answers
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MySQL - Using COUNT(*) in the WHERE clause
...
try this;
select gid
from `gd`
group by gid
having count(*) > 10
order by lastupdated desc
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How to implement LIMIT with SQL Server?
...ders AS
(
SELECT SalesOrderID, OrderDate,
ROW_NUMBER() OVER (ORDER BY OrderDate) AS 'RowNumber'
FROM Sales.SalesOrderHeader
)
SELECT *
FROM OrderedOrders
WHERE RowNumber BETWEEN 10 AND 20;
or something like this for 2000 and below versions...
SELECT TOP 10 * FROM (SELECT TOP 20 FR...
How do I delete rows in a data frame?
...d keep the complement of that set.
In R, the complement of a set is given by the '-' operator.
So, assuming the data.frame is called myData:
myData[-c(2, 4, 6), ] # notice the -
Of course, don't forget to "reassign" myData if you wanted to drop those rows entirely---otherwise, R just prints t...
MySql : Grant read only options?
...ng" from tables and views is the SELECT privilege. If that's what you mean by "all read" then yes:
GRANT SELECT ON *.* TO 'username'@'host_or_wildcard' IDENTIFIED BY 'password';
However, it sounds like you mean an ability to "see" everything, to "look but not touch." So, here are the other kinds...