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Filter Java Stream to 1 and only 1 element
...lements in a LinkedList . I want to guarantee, however, that there is one and only one match to the filter criteria.
20 An...
Regular vs Context Free Grammars
I'm studying for my computing languages test, and there's one idea I'm having problems wrapping my head around.
8 Answe...
Regular Expression for alphanumeric and underscores
...e to have a regular expression that checks if a string contains only upper and lowercase letters, numbers, and underscores.
...
Regex for password must contain at least eight characters, at least one number and both lower and up
...
Minimum eight characters, at least one letter and one number:
"^(?=.*[A-Za-z])(?=.*\d)[A-Za-z\d]{8,}$"
Minimum eight characters, at least one letter, one number and one special character:
"^(?=.*[A-Za-z])(?=.*\d)(?=.*[@$!%*#?&])[A-Za-z\d@$!%*#?&]{8,}$"
Mini...
What is the difference between quiet NaN and signaling NaN?
I have read about floating-point and I understand that NaN could result from operations. But I can't understand what these are concepts exactly. What is the difference between them?
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Are arrays in PHP copied as value or as reference to new variables, and when passed to functions?
...e
copying. Use the reference operator to
copy an array by reference.
And the given example :
<?php
$arr1 = array(2, 3);
$arr2 = $arr1;
$arr2[] = 4; // $arr2 is changed,
// $arr1 is still array(2, 3)
$arr3 = &$arr1;
$arr3[] = 4; // now $arr1 and $arr3 are the same
?>
...
Open file via SSH and Sudo with Emacs
...stion|ssh:you@remotehost:/path RET
Which connects firstly as bird@bastion, and from there to you@remotehost:/path
/su: or /sudo: on remote hosts
You can also use this syntax to sudo/su to root (or of course any other user) on a remote host:
C-xC-f /ssh:you@remotehost|sudo:remotehost:/path/to/file RE...
How can I exclude all “permission denied” messages from “find”?
...
Note:
* This answer probably goes deeper than the use case warrants, and find 2>/dev/null may be good enough in many situations. It may still be of interest for a cross-platform perspective and for its discussion of some advanced shell techniques in the interest of finding a solution that i...
Overloading Macro on Number of Arguments
I have two macros FOO2 and FOO3 :
8 Answers
8
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Why is SSE scalar sqrt(x) slower than rsqrt(x) * x?
I've been profiling some of our core math on an Intel Core Duo, and while looking at various approaches to square root I've noticed something odd: using the SSE scalar operations, it is faster to take a reciprocal square root and multiply it to get the sqrt, than it is to use the native sqrt opcode!...