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How to check if a variable is null or empty string or all whitespace in JavaScript?
...specific question. This is important because op may NOT want to catch things like tabs, for example.
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./configure : /bin/sh^M : bad interpreter [duplicate]
I've been trying to install lpng142 on my fed 12 system. Seems like a problem to me. I get this error
15 Answers
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When do I use fabs and when is it sufficient to use std::abs?
I assume that abs and fabs are behaving different when using math.h . But when I use just cmath and std::abs , do I have to use std::fabs or fabs ? Or isn't this defined?
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Difference between a theta join, equijoin and natural join
I'm having trouble understanding relational algebra when it comes to theta joins, equijoins and natural joins. Could someone please help me better understand it? If I use the = sign on a theta join is it exactly the same as just using a natural join?
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Does Dart support enumerations?
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Beginning 1.8, you can use enums like this:
enum Fruit {
apple, banana
}
main() {
var a = Fruit.apple;
switch (a) {
case Fruit.apple:
print('it is an apple');
break;
}
// get all the values of the e...
Difference between DOM parentNode and parentElement
...ox 9 and to DOM4, but it has been present in all other major browsers for ages.
In most cases, it is the same as parentNode. The only difference comes when a node's parentNode is not an element. If so, parentElement is null.
As an example:
document.body.parentNode; // the <html> element
doc...
How do you find the row count for all your tables in Postgres
I'm looking for a way to find the row count for all my tables in Postgres. I know I can do this one table at a time with:
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Check whether a path is valid
I am just wondering: I am looking for a way to validate if a given path is valid.
(Note: I do not want to check if a file is existing! I only want to proof the validity of the path - So if a file could possibly exists at the location) .
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How do I specify multiple targets in my podfile for my Xcode project?
I'm using CocoaPods with my Xcode 4 project and I have three targets for my project (the default, one for building a lite version and one for building a demo version). All the targets use the same libraries, but CocoaPods is only adding the static library and search paths to the primary target. My p...
not None test in Python [duplicate]
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if val is not None:
# ...
is the Pythonic idiom for testing that a variable is not set to None. This idiom has particular uses in the case of declaring keyword functions with default parameters. is tests identity in Python. Because there is one and only one instance of None present ...