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Check if a class is derived from a generic class
...heck.IsGenericType ? toCheck.GetGenericTypeDefinition() : toCheck;
if (generic == cur) {
return true;
}
toCheck = toCheck.BaseType;
}
return false;
}
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How to check if an email address exists without sending an email?
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There are two methods you can sometimes use to determine if a recipient actually exists:
You can connect to the server, and issue a VRFY command. Very few servers support this command, but it is intended for exactly this. If the server responds with a 2.0.0 DSN, the user exists.
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Shortest distance between a point and a line segment
... const float l2 = length_squared(v, w); // i.e. |w-v|^2 - avoid a sqrt
if (l2 == 0.0) return distance(p, v); // v == w case
// Consider the line extending the segment, parameterized as v + t (w - v).
// We find projection of point p onto the line.
// It falls where t = [(p-v) . (w-v)] /...
How to get the caret column (not pixels) position in a textarea, in characters, from the start?
..., so you will have to do something like this:
function getCaret(node) {
if (node.selectionStart) {
return node.selectionStart;
} else if (!document.selection) {
return 0;
}
var c = "\001",
sel = document.selection.createRange(),
dul = sel.duplicate(),
len = 0;
...
How can I check if a file exists in Perl?
... given path using the -e file-test operator.
print "$base_path exists!\n" if -e $base_path;
However, this test is probably broader than you intend. The code above will generate output if a plain file exists at that path, but it will also fire for a directory, a named pipe, a symlink, or a more ex...
How to implement a binary tree?
...f getRoot(self):
return self.root
def add(self, val):
if self.root is None:
self.root = Node(val)
else:
self._add(val, self.root)
def _add(self, val, node):
if val < node.v:
if node.l is not None:
self._...
Jinja2 template variable if None Object set a default value
How to make a variable in jijna2 default to "" if object is None instead of doing something like this?
9 Answers
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How can I check if a key exists in a dictionary? [duplicate]
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if key in array:
# do something
Associative arrays are called dictionaries in Python and you can learn more about them in the stdtypes documentation.
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Is there a Python equivalent of the C# null-coalescing operator?
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other = s or "some default value"
Ok, it must be clarified how the or operator works. It is a boolean operator, so it works in a boolean context. If the values are not boolean, they are converted to boolean for the purposes of the operator.
Note that the or operator does not r...
How to convert number to words in java
...= {
"",
" ten",
" twenty",
" thirty",
" forty",
" fifty",
" sixty",
" seventy",
" eighty",
" ninety"
};
private static final String[] numNames = {
"",
" one",
" two",
" three",
" four",
" five",
" six",
" seven",
" eigh...