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How do I implement basic “Long Polling”?
...how error handling in the coming Javascript example)
msgsrv.php
<?php
if(rand(1,3) == 1){
/* Fake an error */
header("HTTP/1.0 404 Not Found");
die();
}
/* Send a string after a random number of seconds (2-10) */
sleep(rand(2,10));
echo("Hi! Have a random number: " . rand(1,10));
?...
Cmake doesn't find Boost
...Make, but it fails to find Boost libraries even though they are in the specified folder. I have specified Boost_INCLUDE_DIR , Boost_LIBRARYDIR and BOOST_ROOT , but I still get an error saying that CMake is not able to find Boost. What could be the reason of such error?
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String variable interpolation Java [duplicate]
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If you're using Java 5 or higher, you can use String.format:
urlString += String.format("u1=%s;u2=%s;u3=%s;u4=%s;", u1, u2, u3, u4);
See Formatter for details.
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round() doesn't seem to be rounding properly
...to blame here -- "5.665 -> 5.67" but "15.665 -> 15.66". Use decimals if you need exact precision.
– Jimmy
Jul 15 '15 at 22:42
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Relative frequencies / proportions with dplyr
Suppose I want to calculate the proportion of different values within each group. For example, using the mtcars data, how do I calculate the relative frequency of number of gears by am (automatic/manual) in one go with dplyr ?
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Get the current first responder without using a private API
... me that my app cannot be accepted because I'm using a non-public API; specifically, it says,
28 Answers
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Simplest way to do a recursive self-join?
...e parent node is defined by the topmost (anchor) query in the WITH clause. If you need specifics, please create a fiddle on sqlfiddle.com and post the link here.
– Quassnoi
Nov 25 '14 at 22:31
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Find and extract a number from a string
...tring b = string.Empty;
int val;
for (int i=0; i< a.Length; i++)
{
if (Char.IsDigit(a[i]))
b += a[i];
}
if (b.Length>0)
val = int.Parse(b);
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improve this answer
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How to concatenate strings with padding in sqlite
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Just one more line for @tofutim answer ... if you want custom field name for concatenated row ...
SELECT
(
col1 || '-' || SUBSTR('00' || col2, -2, 2) | '-' || SUBSTR('0000' || col3, -4, 4)
) AS my_column
FROM
mytable;
Tested on SQLite 3.8.8.3, Thanks!
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Should I use an exception specifier in C++?
In C++, you can specify that a function may or may not throw an exception by using an exception specifier. For example:
14 ...