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Why doesn't delete set the pointer to NULL?
...nment anyway.
Also, it would render the following code illegal:
T* const foo = new T;
delete foo;
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How to access environment variable values?
... "how to check environment variables in Python."
Here's how to check if $FOO is set:
try:
os.environ["FOO"]
except KeyError:
print "Please set the environment variable FOO"
sys.exit(1)
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Get value of a string after last slash in JavaScript
...
At least three ways:
A regular expression:
var result = /[^/]*$/.exec("foo/bar/test.html")[0];
...which says "grab the series of characters not containing a slash" ([^/]*) at the end of the string ($). Then it grabs the matched characters from the returned match object by indexing into it ([0]...
Selecting and manipulating CSS pseudo-elements such as ::before and ::after using jQuery
...a attribute and then use jQuery to manipulate that:
In HTML:
<span>foo</span>
In jQuery:
$('span').hover(function(){
$(this).attr('data-content','bar');
});
In CSS:
span:after {
content: attr(data-content) ' any other text you may want';
}
If you want to prevent the 'o...
How do I disable the resizable property of a textarea?
...of options.
To disable a specific textarea with the name attribute set to foo (i.e., <textarea name="foo"></textarea>):
textarea[name=foo] {
resize: none;
}
Or, using an id attribute (i.e., <textarea id="foo"></textarea>):
#foo {
resize: none;
}
The W3C page lists ...
Malloc vs new — different padding
...e's talking about is more than a straight difference between malloc(sizeof(Foo) * n) vs new Foo[n]. Maybe it's more like:
malloc((sizeof(int) + sizeof(char)) * n);
vs.
struct Foo { int a; char b; }
new Foo[n];
That is, maybe he's saying "I use malloc", but means "I manually pack the data into ...
Variable interpolation in the shell
... are the only way to prevent parameter expansion. For example, "$filepath"_foo and ${filepath}_foo would both expand to /tmp/name_foo. However, '$filepath'_foo, "$"filepath_foo, and $"filepath"_foo would all avoid expansion completely. This is why export PATH=$PATH:$addpath works to add :$addpath (w...
Delete an element from a dictionary
...e del statement is what you're looking for. If you have a dictionary named foo with a key called 'bar', you can delete 'bar' from foo like this:
del foo['bar']
Note that this permanently modifies the dictionary being operated on. If you want to keep the original dictionary, you'll have to create ...
Return None if Dictionary key is not available
...f __getitem__(self, key):
return dict.get(self, key)
>>> foo = NoneDict([(1,"asdf"), (2,"qwerty")])
>>> foo[1]
'asdf'
>>> foo[2]
'qwerty'
>>> foo[3] is None
True
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#pragma once vs include guards? [duplicate]
...ged reliability problem with #pragma once. If I have two different headers foo/string.h and bar/string.h then putting a #pragma once means I'm allowed to include each of them once, but including both of them is also OK. If I use an include guard, then I will probably write something like #ifndef STR...