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Accessing members of items in a JSONArray with Java
...; jsonItems = IntStream.range(0, jsonArray.length())
.mapToObj(index -> (JSONObject) jsonArray.get(index))
.collect(Collectors.toList());
// you can access the array elements now
jsonItems.forEach(arrayElement -> System.out.println(arrayElement.get("a")));
...
Add new row to dataframe, at specific row-index, not appended?
... 17
3 3 8 13 18
4 1 2 3 4
41 4 9 14 19
5 5 10 15 20
(Note we index r differently).
And finally, benchmarks:
library(microbenchmark)
microbenchmark(
rbind(existingDF[1:r,],newrow,existingDF[-(1:r),]),
insertRow(existingDF,newrow,r)
)
Unit: microseconds
...
TypeError: 'dict_keys' object does not support indexing
...ect which behaves a lot more like a set than a list. As such, it can't be indexed.
The solution is to pass list(d.keys()) (or simply list(d)) to shuffle.
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Is there a “previous sibling” selector?
...ing selector can be simulated in CSS using the flex order property.
The z-index Myth
Another long-standing belief has been that z-index works only on positioned elements.
In fact, the most current version of the spec – the W3C Editor's Draft – still asserts this to be true:
9.9.1 Specifyi...
Loop inside React JSX
...dy>
{rows.map(function (i) {
return <ObjectRow key={i} index={i} />;
})}
</tbody>
);
}
With ES2015 syntax & Array methods
With Array.prototype.fill you could do this as an alternative to using spread as illustrated above:
<tbody>
{Array(10).fi...
SQL JOIN vs IN performance?
...ut as soon as you start using OUTER JOIN, or if you're lacking foreign key indexes, the IN might be quicker.
Marc
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What is the most effective way to get the index of an iterator of an std::vector?
I'm iterating over a vector and need the index the iterator is currently pointing at. AFAIK this can be done in two ways:
9...
Git undo changes in some files [duplicate]
...th the changes to the file A. If you have not yet added the changes to the index or committed them, then you just want to use the checkout command - this will change the state of the working copy to match the repository:
git checkout A
If you added it to the index already, use reset:
git reset A...
Left Align Cells in UICollectionView
... use.
CGFloat maxY = -1.0f;
//this loop assumes attributes are in IndexPath order
for (UICollectionViewLayoutAttributes *attribute in attributes) {
if (attribute.frame.origin.y >= maxY) {
leftMargin = self.sectionInset.left;
}
attribute.frame = CG...
Advantages and disadvantages of GUID / UUID database keys
...t, and I thought I should point out a big downside of GUID PK's: Clustered Indexes.
If you have a lot of records, and a clustered index on a GUID, your insert performance will SUCK, as you get inserts in random places in the list of items (thats the point), not at the end (which is quick)
So if yo...