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Circle line-segment collision detection algorithm?
...
(x - h)2 + (y - k)2 = r2
(h,k) = center of circle.
Note: We've simplified the problem to 2D here, the solution we get applies also in 3D
to get:
Expand
x2 - 2xh + h2 + y2 - 2yk + k2 - r2 = 0
Plug
x = ex + tdx
y = ey + tdy
( ex + tdx )2 - 2( ex + tdx )h + h2 +
( ey + tdy )2 - 2( ey + tdy ...
Mysql: Select rows from a table that are not in another
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If you have 300 columns as you mentioned in another comment, and you want to compare on all columns (assuming the columns are all the same name), you can use a NATURAL LEFT JOIN to implicitly join on all matching column names...
Pinging servers in Python
In Python, is there a way to ping a server through ICMP and return TRUE if the server responds, or FALSE if there is no response?
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Inserting a text where cursor is using Javascript/jquery
...Caret(areaId, text) {
var txtarea = document.getElementById(areaId);
if (!txtarea) {
return;
}
var scrollPos = txtarea.scrollTop;
var strPos = 0;
var br = ((txtarea.selectionStart || txtarea.selectionStart == '0') ?
"ff" : (document.selection ? "ie" : false));
if (br...
How to tell Jackson to ignore a field during serialization if its value is null?
How can Jackson be configured to ignore a field value during serialization if that field's value is null.
19 Answers
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CURL alternative in Python
...ON decoding is handy as well. No need to manually load the body with json if the appropriate content-type is set.
– Thomas Farvour
Dec 17 '13 at 21:36
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Postgres: INSERT if does not exist already
...sert on this blog (in the updated area at the bottom) including some links if you want to read more about the details.
– Skyguard
Apr 1 '17 at 16:03
22
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When to use Cast() and Oftype() in Linq
...y be cast to type x.
Cast - will try to cast all the elements into type x. if some of them are not from this type you will get InvalidCastException
EDIT
for example:
object[] objs = new object[] { "12345", 12 };
objs.Cast<string>().ToArray(); //throws InvalidCastException
objs.OfType<stri...
How to show a confirm message before delete?
... a confirm message on clicking delete (this maybe a button or an image). If the user selects ' Ok ' then delete is done, else if ' Cancel ' is clicked nothing happens.
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execute function after complete page load
...ener('DOMContentLoaded', function() {
// your code here
}, false);
or
if your comfort with jquery,
$(document).ready(function(){
// your code
});
$(document).ready() fires on DOMContentLoaded, but this event is not being fired consistently among browsers. This is why jQuery will most probabl...