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Is there a way to detect if an image is blurry?
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Yes, it is. Compute the Fast Fourier Transform and analyse the result. The Fourier transform tells you which frequencies are present in the image. If there is a low amount of high frequencies, then the image is blurry.
Defining the terms 'low' and 'high' is up to you.
E...
What makes Lisp macros so special?
...not had the privilege of using Lisp macros. As someone who wants to understand the buzz, please explain what makes this feature so powerful.
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Using IQueryable with Linq
...ing data from a table in two ways, one which returns IEnumerable<T>, and one which returns an IQueryable<T>. Say, for example, you have a Products table, and you want to get all of the products whose cost is >$25.
If you do:
IEnumerable<Product> products = myORM.GetProducts(...
How to position a DIV in a specific coordinates?
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Script its left and top properties as the number of pixels from the left edge and top edge respectively. It must have position: absolute;
var d = document.getElementById('yourDivId');
d.style.position = "absolute";
d.style.left = x_pos+'px...
how does multiplication differ for NumPy Matrix vs Array classes?
... to avoid using the matrix class is that a) it's inherently 2-dimensional, and b) there's additional overhead compared to a "normal" numpy array. If all you're doing is linear algebra, then by all means, feel free to use the matrix class... Personally I find it more trouble than it's worth, though.
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Check if a string matches a regex in Bash script
...=~ ^regex$ ]] && echo "matched" || echo "did not match"
where commands after && are executed if the test is successful, and commands after || are executed if the test is unsuccessful.
Note this is based on the solution by Aleks-Daniel Jakimenko in User input date format verification...
Can I change the checkbox size using CSS?
...oz-transform: scale(2); /* FF */
-webkit-transform: scale(2); /* Safari and Chrome */
-o-transform: scale(2); /* Opera */
transform: scale(2);
padding: 10px;
}
/* Might want to wrap a span around your checkbox text */
.checkboxtext
{
/* Checkbox text */
font-size: 110%;
di...
How to include “zero” / “0” results in COUNT aggregate?
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You want an outer join for this (and you need to use person as the "driving" table)
SELECT person.person_id, COUNT(appointment.person_id) AS "number_of_appointments"
FROM person
LEFT JOIN appointment ON person.person_id = appointment.person_id
GROUP BY p...
BigDecimal setScale and round
...lluded to but not directly addressed is the difference between "precision" and "scale" and how they are used in the two statements. "precision" is the total number of significant digits in a number. "scale" is the number of digits to the right of the decimal point.
The MathContext constructor onl...
Eclipse, regular expression search and replace
... as part of the replace string when performing a regular expression search and replace?
5 Answers
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