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Test whether a glob has any matches in bash
...compgen -G "<glob-pattern>"
Escape the pattern or it'll get pre-expanded into matches.
Exit status is:
1 for no-match,
0 for 'one or more matches'
stdout is a list of files matching the glob.
I think this is the best option in terms of conciseness and minimizing potential side effect...
In javascript, is an empty string always false as a boolean?
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Yes. Javascript is a dialect of ECMAScript, and ECMAScript language specification clearly defines this behavior:
ToBoolean
The result is false if the argument is the empty String (its length is zero);
otherwise the result is true
Quote taken from http://www.ecma-inte...
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
?>
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Global and local variables in R
I am a newbie for R, and I am quite confused with the usage of local and global variables in R.
3 Answers
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“Could not find any information for class named ViewController”
...roject.
Steps:
In the project file explorer (left panel) find the class and right click -> Delete
Remove reference (do not move to trash as you will lose the class for good)
Right click on the folder that contained the class -> Add files to ...
Find the class you just deleted in the file sy...
Animate scrollTop not working in firefox
...llback to be invoked twice. Browser-detection features have been suggested and subsequently deprecated, and some are arguably rather far-fetched.
If the callback is idempotent and doesn't require a lot of computing power, firing it twice may be a complete non-issue. If multiple invocations of the c...
Rotating and spacing axis labels in ggplot2
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In the newest version of ggplot2 the command would be: q + theme(axis.text.x=element_text(angle = -90, hjust = 0))
– rnorberg
Sep 28 '12 at 13:18
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Python != operation vs “is not”
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== is an equality test. It checks whether the right hand side and the left hand side are equal objects (according to their __eq__ or __cmp__ methods.)
is is an identity test. It checks whether the right hand side and the left hand side are the very same object. No methodcalls ...
bash: mkvirtualenv: command not found
...erage the chance that virtualenvwrapper.sh is already in your shell's PATH and just issue a source `which virtualenvwrapper.sh`
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How to complete a git clone for a big project on an unstable connection?
...codebase, but at the moment I have an internet connection of about 300kbps and it's just anything but stable. I can get the connection back any moment, but then the git clone process already stopped working, and no way to get it running again. Is there some way to have a more failure-resistant git c...