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Difference between `const shared_ptr` and `shared_ptr`?
...);
sA->a = 4; // compile-error
return sA;
}
int main(int argc, char** argv) {
f1();
f2();
return 0;
}
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How to select the row with the maximum value in each group
In a dataset with multiple observations for each subject I want to take a subset with only the maximum data value for each record. For example, with a following dataset:
...
Select between two dates with Django
I am looking to make a query that selects between dates with Django.
4 Answers
4
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How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly
... 0.0 NaN 0.0
3 0.0 1.0 2.0 3.0
4 NaN 0.0 NaN NaN
If you want to select the rows that have two or more columns with null value, you run the following:
>>> qty_of_nuls = 2
>>> df.iloc[df[(df.isnull().sum(axis=1) >=qty_of_nuls)].index]
0 1 2 3
1 0.0 NaN 0...
Convert an image (selected by path) to base64 string
How do you convert an image from a path on the user's computer to a base64 string in C#?
12 Answers
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Use LINQ to get items in one List, that are not in another List
...erride the equality:
var excludedIDs = new HashSet<int>(peopleList1.Select(p => p.ID));
var result = peopleList2.Where(p => !excludedIDs.Contains(p.ID));
This variant does not remove duplicates.
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How do I pass JavaScript variables to PHP?
...larieids">SalarieID:</label>
<?php
$query = "SELECT * FROM salarie";
$result = mysql_query($query);
if ($result) :
?>
<select id="salarieids" name="salarieid">
<?php
while ($row = mysql_fetch_assoc($r...
Displaying files (e.g. images) stored in Google Drive on a website
...kit, the following worked for me:
1 Make a folder called e.g. "public"
2 Select that folder, right click and Share > Share. Click. Select "Anyone can access"
3 Drag and Drop a file into the folder, and let it upload.
4 Right click on the file and select Details. One of the lines in the Detail...
Does PostgreSQL support “accent insensitive” collations?
...n unaccent() you can use with your example (where LIKE seems not needed).
SELECT *
FROM users
WHERE unaccent(name) = unaccent('João');
Index
To use an index for that kind of query, create an index on the expression. However, Postgres only accepts IMMUTABLE functions for indexes. If a functio...
SET NOCOUNT ON usage
...OUNT is ON. Depends on client lib implementation in cases when query holds SELECT statements or RPC calls that do select, it may require to disable counting... WHEN disabled, rows are still counted for select statement, but flag DONE_COUNT is set to false. Always read what your client lib suggests s...