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Group a list of objects by an attribute : Java
I need to group a list of objects(Student) using an attribute(Location) of the particular object, the code is like below,
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Python Regex - How to Get Positions and Values of Matches
...e.compile("[a-z]")
for m in p.finditer('a1b2c3d4'):
print(m.start(), m.group())
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How to select unique records by SQL
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If you only need to remove duplicates then use DISTINCT. GROUP BY should be used to apply aggregate operators to each group
GROUP BY v DISTINCT
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How to use GROUP BY to concatenate strings in SQL Server?
...xt())[1]','VARCHAR(MAX)')
,1,2,'') AS NameValues
FROM #YourTable Results
GROUP BY ID
DROP TABLE #YourTable
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data.table vs dplyr: can one do something well the other can't or does poorly?
...consistency in syntax.
1. Speed
Quite a few benchmarks (though mostly on grouping operations) have been added to the question already showing data.table gets faster than dplyr as the number of groups and/or rows to group by increase, including benchmarks by Matt on grouping from 10 million to 2 bi...
nginx error connect to php5-fpm.sock failed (13: Permission denied)
...on.
Uncomment all permission lines, like:
listen.owner = www-data
listen.group = www-data
listen.mode = 0660
Restart fpm - sudo service php5-fpm restart or sudo service php7.0-fpm restart
Note: if your webserver runs as user other than www-data, you will need to update the www.conf file accordi...
Group by & count function in sqlalchemy
I want a "group by and count" command in sqlalchemy. How can I do this?
3 Answers
3
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MySQL: Sort GROUP_CONCAT values
In short: Is there any way to sort the values in a GROUP_CONCAT statement?
2 Answers
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Group by with multiple columns using lambda
How can I group by with multiple columns using lambda?
5 Answers
5
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How do I find duplicate values in a table in Oracle?
...ater than one time.
SELECT column_name, COUNT(column_name)
FROM table_name
GROUP BY column_name
HAVING COUNT(column_name) > 1;
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