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SQL Query to concatenate column values from multiple rows in Oracle
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10 Answers
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Is it fine to have foreign key as primary key?
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134
Foreign keys are almost always "Allow Duplicates," which would make them unsuitable as Primary...
what is faster: in_array or isset? [closed]
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The answers so far are spot-on. Using isset in this case is faster because
It uses an O(1) h...
Is there a way to pass optional parameters to a function?
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The Python 2 documentation, 7.6. Function definitions gives you a couple of ways to detect whe...
R programming: How do I get Euler's number?
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The R expression
exp(1)
represents e, and
exp(2)
represents e^2.
This works because exp...
Concatenate two slices in Go
I'm trying to combine the slice [1, 2] and the slice [3, 4] . How can I do this in Go?
7 Answers
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Python's json module, converts int dictionary keys to strings
... for the given language, are strings (or "scalars" in Perl). In perl $foo{1}, $foo{1.0}, and $foo{"1"} are all references to the same mapping in %foo --- the key is evaluated as a scalar!
JSON started as a Javascript serialization technology. (JSON stands for JavaScript Object Notation.) Naturall...
How can I get the diff between all the commits that occurred between two dates with Git?
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11 Answers
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Pandas aggregate count distinct
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153
How about either of:
>>> df
date duration user_id
0 2013-04-01 30 ...