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Select first 4 rows of a data.frame in R
How can I select the first 4 rows of a data.frame :
5 Answers
5
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Linq to Entities join vs groupjoin
...Join syntax would be
from p in Parent
join c in Child on p.Id equals c.Id
select new { p.Value, c.ChildValue }
returning an IEnumerable<X> where X is an anonymous type with two properties, Value and ChildValue. This query syntax uses the Join method under the hood.
GroupJoin syntax would be
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Displaying the Indian currency symbol on a website
...e and pastes it somewhere else, he will see Rs and not some other or blank character.
You can now also use the new Rupee unicode symbol — U+20B9 INDIAN RUPEE SIGN. It can be used in this manner:
<span class="WebRupee">&#x20B9;</span> 500
Just include the following script and it...
Select element by exact match of its content
All right, I wonder if there is a way to make the :contains() jQuery's selector to select elements with only the string that is typed in
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How do I generate a constructor from class fields using Visual Studio (and/or ReSharper)?
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ReSharper offers a Generate Constructor tool where you can select any field/properties that you want initialized. I use the Alt + Ins hot-key to access this.
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SQL Group By with an Order By
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In all versions of MySQL, simply alias the aggregate in the SELECT list, and order by the alias:
SELECT COUNT(id) AS theCount, `Tag` from `images-tags`
GROUP BY `Tag`
ORDER BY theCount DESC
LIMIT 20
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Set keyboard caret position in html textbox
...tRange();
range.move('character', caretPos);
range.select();
}
else {
if(elem.selectionStart) {
elem.focus();
elem.setSelectionRange(caretPos, caretPos);
}
else
elem.focus();
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Return 0 if field is null in MySQL
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Would that be IFNULL((SELECT SUM(uop.price * uop.qty) FROM uc_order_products uop WHERE uo.order_id = uop.order_id) AS products_subtotal, 0)?
– Kevin
Oct 22 '10 at 13:46
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SQL query for finding records where count > 1
...ers that have more than one payment per day with the same account number
SELECT
user_id ,
COUNT(*) count
FROM
PAYMENT
GROUP BY
account,
user_id ,
date
Having
COUNT(*) > 1
Update
If you want to only include those that have a distinct ZIP you can get a distinct set first and then perfor...
What is the easiest way to initialize a std::vector with hardcoded elements?
...typesafe, compile time constant
template <typename T, std::size_t N>
char (&sizeof_array( T(&)[N] ))[N]; // declared, undefined
#define ARRAY_SIZE(x) sizeof(sizeof_array(x))
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