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How does one reorder columns in a data frame?
...s keep all the rows, and the 1,2,3,4 refers to the columns.
To change the order as in the above question do df2[,c(1,3,2,4)]
If you want to output this file as a csv, do write.csv(df2, file="somedf.csv")
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Converting an array of objects to ActiveRecord::Relation
...ECT .... WHERE `my_models`.id IN (2, 3, 4, 6, ....
Keep in mind that the ordering of the array will be lost - But since your objective is only to run a class method on the collection of these objects, I assume it won't be a problem.
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What is difference between Collection.stream().forEach() and Collection.forEach()?
...number of subtle differences that might be significant.
One issue is with ordering. With Stream.forEach, the order is undefined. It's unlikely to occur with sequential streams, still, it's within the specification for Stream.forEach to execute in some arbitrary order. This does occur frequently in ...
When to use DataContract and DataMember attributes?
...non-public properties or fields
without [DataMember], you cannot define an order of serialization (Order=) and the DCS will serialize all properties alphabetically
without [DataMember], you cannot define a different name for your property (Name=)
without [DataMember], you cannot define things like I...
Reminder - \r\n or \n\r?
...ater look at a PC keyboard, see the key called "Enter," and get the letter order wrong!
– Rob Kennedy
Jun 30 '11 at 19:36
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c++ boost::multi_index composite keys efficiency - c++1y / stl - 清泛IT社区，为创新赋能！
...cumentation states that "Composite keys are sorted by lexicographical order, i.e. sorting is performed by the first key, then the second key if the first one is equal, etc". Does this mean that the structure is stored such that a lookup for a specific 2-part composite key will take O(n=1) ...
PostgreSQL: Modify OWNER on all tables simultaneously in PostgreSQL
...ROM pg_tables WHERE NOT schemaname IN ('pg_catalog', 'information_schema')
ORDER BY schemaname, tablename;
Sequences
SELECT 'ALTER SEQUENCE '|| sequence_schema || '.' || sequence_name ||' OWNER TO my_new_owner;'
FROM information_schema.sequences WHERE NOT sequence_schema IN ('pg_catalog', 'inform...
How to get Last record from Sqlite?
...LE);
OR
you can also used following solution:
SELECT * FROM tablename ORDER BY column DESC LIMIT 1;
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GROUP BY with MAX(DATE) [duplicate]
...e FROM (
SELECT train, dest, time,
RANK() OVER (PARTITION BY train ORDER BY time DESC) dest_rank
FROM traintable
) where dest_rank = 1
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Sorting data based on second column of a file
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Faced issue with "wrong" ordering. Pay attention to man "*** WARNING *** The locale specified by the environment affects sort order. Set LC_ALL=C to get the traditional sort order that uses native byte values." (for string match case without -n)
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