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decorators in the python standard lib (@deprecated specifically)
...ed
when the function is used."""
@functools.wraps(func)
def new_func(*args, **kwargs):
warnings.simplefilter('always', DeprecationWarning) # turn off filter
warnings.warn("Call to deprecated function {}.".format(func.__name__),
category=DeprecationW...
Using @property versus getters and setters
...de world. There are plenty of ways to do this in Python (getattr, setattr, __getattribute__, etc..., but a very concise and clean one is:
def set_email(self, value):
if '@' not in value:
raise Exception("This doesn't look like an email address.")
self._email = value
def get_email(s...
Error handling in Bash
...up() {
rm -f "${tempfiles[@]}"
}
trap cleanup 0
error() {
local parent_lineno="$1"
local message="$2"
local code="${3:-1}"
if [[ -n "$message" ]] ; then
echo "Error on or near line ${parent_lineno}: ${message}; exiting with status ${code}"
else
echo "Error on or near line ${pare...
Remove last item from array
...
learn by example:
let array_1 = [1,2,3,4];
let array_2 = [1,2,3,4];
let array_3 = [1,2,3,4];
array_1.splice(-1,1) // output --> [4] array_1 = [1,2,3]
array_2.slice(0,-1); // output --> [1,2,3] array_2 = [1,2,3,4]
array_3.pop(); //...
Extract value of attribute node via XPath
...
you can select name attribute of all child nodes in one go.
name="Child_2"
name="Child_4"
name="Child_1"
name="Child_3"
name="Child_1"
name="Child_2"
name="Child_4"
name="Child_3"
share
|
impro...
How do I calculate square root in Python?
...ethod can be computed as: sqrt = x**(float(1)/2)
– VM_AI
Sep 28 '18 at 10:41
add a comment
|
...
class
...odule ("static") methods:
class String
class << self
def value_of obj
obj.to_s
end
end
end
String.value_of 42 # => "42"
This can also be written as a shorthand:
class String
def self.value_of obj
obj.to_s
end
end
Or even shorter:
def String.value_of obj
...
How to reshape data from long to wide format
...
@indra_patil - I would likely use the reshape2 package as indicated in one of the other answers. You could create a new question that's specific to your use case and post it if you can't figure it out.
– Chase...
Is there a math nCr function in python? [duplicate]
...
def nCr(n,r):
f = math.factorial
return f(n) / f(r) / f(n-r)
if __name__ == '__main__':
print nCr(4,2)
In Python 3, use the integer division // instead of / to avoid overflows:
return f(n) // f(r) // f(n-r)
Output
6
...
Difference between JSON.stringify and JSON.parse
...pt object into JSON text and stores that JSON text in a string, eg:
var my_object = { key_1: "some text", key_2: true, key_3: 5 };
var object_as_string = JSON.stringify(my_object);
// "{"key_1":"some text","key_2":true,"key_3":5}"
typeof(object_as_string);
// "string"
JSON.parse turns a...