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Key existence check in HashMap
...
Do you ever store a null value? If not, you can just do:
Foo value = map.get(key);
if (value != null) {
...
} else {
// No such key
}
Otherwise, you could just check for existence if you get a null value returned:
Foo value = map.get(key);
if (value != null) {
...
} ...
Add a prefix to all Flask routes
..._)
app.debug = True
app.wsgi_app = PrefixMiddleware(app.wsgi_app, prefix='/foo')
@app.route('/bar')
def bar():
return "The URL for this page is {}".format(url_for('bar'))
if __name__ == '__main__':
app.run('0.0.0.0', 9010)
Visit http://localhost:9010/foo/bar,
You will get the right re...
Is there a better way to express nested namespaces in C++ within the header
...HELPER, _Namespace, __VA_ARGS__)
Now you can do this:
NAMESPACE_BEGIN(Foo, Bar, Baz)
class X { };
NAMESPACE_END(Baz, Bar, Foo) // order doesn't matter, NAMESPACE_END(a, b, c) would work equally well
Foo::Bar::Baz::X x;
For nesting deeper than three levels you would have to add helper macro...
Cocoa: What's the difference between the frame and the bounds?
UIView and its subclasses all have the properties frame and bounds . What's the difference?
12 Answers
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Collapse sequences of white space into a single character and trim string
...ling spaces, and eliminate all of them. it won't deal with "hello foo"
– Brian Postow
Sep 15 '09 at 14:09
2
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Read environment variables in Node.js
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this also works for assigning variables. process.env.FOO = "foo"; works.
– chicks
Sep 11 '15 at 17:16
16
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List files with certain extensions with ls and grep
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When I run ls foo*.{tar.gz,zip} directly in a shell it works, but when put this inside a shell script latest=$(ls -I '.done' -tr ${pkgprefix}.{tar.gz,zip} | tail -1) I got an error message: ls: cannot access 'bamtools*.{tar.gz,zip}': No s...
Difference between global and device functions
...l settings. You can also "overload" a function, e.g : you can declare void foo(void) and __device__ foo (void), then one is executed on the host and can only be called from a host function. The other is executed on the device and can only be called from a device or kernel function.
You can also vis...
Deleting Objects in JavaScript
... an object key in your case
var obj = { helloText: "Hello World!" };
var foo = obj;
delete obj;
object is not deleted check obj still take same values delete usage:
delete obj.helloText
and then check obj, foo, both are empty object.
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Print newline in PHP in single quotes
...pe sequence you can use in single quotes is for the single quote itself.
$foo = 'That\'s great';
The only way you could insert a new line into a string created with single quotes is to insert a literal newline
$bar = 'That\'s
cheating';
...