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Append an object to a list in R in amortized constant time, O(1)?
If I have some R list mylist , you can append an item obj to it like so:
17 Answers
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What is more efficient? Using pow to square or just multiply it with itself?
What of these two methods is in C more efficient? And how about:
7 Answers
7
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Does JavaScript have “Short-circuit” evaluation?
...rcuit" evaluation.
if (true == true || foo.foo){
// Passes, no errors because foo isn't defined.
}
Live DEMO
if (false && foo.foo){
// Passes, no errors because foo isn't defined.
}
Live DEMO
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pandas three-way joining multiple dataframes on columns
...g) names of people, while all the other columns in each dataframe are attributes of that person.
10 Answers
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How to get all subsets of a set? (powerset)
...e has exactly a powerset recipe for this:
from itertools import chain, combinations
def powerset(iterable):
"powerset([1,2,3]) --> () (1,) (2,) (3,) (1,2) (1,3) (2,3) (1,2,3)"
s = list(iterable)
return chain.from_iterable(combinations(s, r) for r in range(len(s)+1))
Output:
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join list of lists in python [duplicate]
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import itertools
a = [['a','b'], ['c']]
print(list(itertools.chain.from_iterable(a)))
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Better way to sum a property value in an array
...erCollection extends Array {
sum(key) {
return this.reduce((a, b) => a + (b[key] || 0), 0);
}
}
const traveler = new TravellerCollection(...[
{ description: 'Senior', Amount: 50},
{ description: 'Senior', Amount: 50},
{ description: 'Adult', Amount: 75},
{ desc...
SQL JOIN and different types of JOINs
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TylerH
18.1k1212 gold badges6161 silver badges8080 bronze badges
answered Nov 30 '13 at 9:34
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Chrome sendrequest error: TypeError: Converting circular structure to JSON
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It means that the object you pass in the request (I guess it is pagedoc) has a circular reference, something like:
var a = {};
a.b = a;
JSON.stringify cannot convert structures like this.
N.B.: This would be the case with DOM nodes, which h...
What is the purpose of Rank2Types?
I am not really proficient in Haskell, so this might be a very easy question.
6 Answers
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