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How many parameters are too many? [closed]
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Cartesian product of multiple arrays in JavaScript
...overly complicated, most of them take 20 lines of code or even more.
This example uses just two lines of vanilla JavaScript, no lodash, underscore or other libraries:
let f = (a, b) => [].concat(...a.map(a => b.map(b => [].concat(a, b))));
let cartesian = (a, b, ...c) => b ? cartesian(f(...
Pandas dataframe get first row of each group
...If you need id as column:
>>> df.groupby('id').first().reset_index()
id value
0 1 first
1 2 first
2 3 first
3 4 second
4 5 first
5 6 first
6 7 fourth
To get n first records, you can use head():
>>> df.groupby('id').head(2).reset_index(drop=True)
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correct way to use super (argument passing)
...s following Python's Super Considered Harmful , and went to test out his examples.
3 Answers
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The static keyword and its various uses in C++
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Variables:
static variables exist for the "lifetime" of the translation unit that it's defined in, and:
If it's in a namespace scope (i.e. outside of functions and classes), then it can't be accessed from any other translation unit. This is known as "i...
Is calculating an MD5 hash less CPU intensive than SHA family functions?
...ng an MD5 hash less CPU intensive than SHA-1 or SHA-2 on "standard" laptop x86 hardware? I'm interested in general information, not specific to a certain chip.
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Remove specific commit
... be a toss up between revert and rebase, and there are no straightforward examples, and the docs assume I know more than I do.
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What is the difference between return and return()?
... is, nothing. The parentheses are allowed because they are allowed in any expression to influence evaluation order, but in your examples they're just superfluous.
return is not a function, but a statement. It is syntactically similar to other simple control flow statements like break and continue t...
Is there a way to 'uniq' by column?
...field 1
Test result:
overflow@domain2.com,2009-11-27 00:58:29.793000000,xx3.net,255.255.255.0
stack2@domain.com,2009-11-27 01:05:47.893000000,xx2.net,127.0.0.1
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typeof for RegExp
Is there anyway to detect if a JavaScript object is a regex?
8 Answers
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