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How can I multiply and divide using only bit shifting and adding?
... to decompose one of the numbers by powers of two, like so:
21 * 5 = 10101_2 * 101_2 (Initial step)
= 10101_2 * (1 * 2^2 + 0 * 2^1 + 1 * 2^0)
= 10101_2 * 2^2 + 10101_2 * 2^0
= 10101_2 << 2 + 10101_2 << 0 (Decomposed)
= 10101_2 * 4 + 10101_2 *...
Algorithm to detect corners of paper sheet in photo
...(in OpenCV use findcontour() with some simple parameters, I think I used CV_RETR_LIST). might still struggle when it's on a white piece of paper, but was definitely providing best results.
For the Houghline2() Transform, try with the CV_HOUGH_STANDARD as opposed to the CV_HOUGH_PROBABILISTIC, it'l...
Split data frame string column into multiple columns
...
Use stringr::str_split_fixed
library(stringr)
str_split_fixed(before$type, "_and_", 2)
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How do I reference an existing branch from an issue in GitHub?
...ant to do this, I manually make the link like this:
[a link to a branch](/_user_/_project_/tree/_branch_)
Where _user_, _project_, and _branch_ should be replaced with the parts of the branch's URL. For example, a branch in GitHub's "linguist" project:
[api-changes branch in github/linguist](/g...
What is function overloading and overriding in php?
...that method.
In PHP, you can only overload methods using the magic method __call.
An example of overriding:
<?php
class Foo {
function myFoo() {
return "Foo";
}
}
class Bar extends Foo {
function myFoo() {
return "Bar";
}
}
$foo = new Foo;
$bar = new Bar;
echo($foo-&...
Where is my Django installation?
...go
<module 'django' from '/usr/local/lib/python2.6/dist-packages/django/__init__.pyc'>
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How do I check if a string is valid JSON in Python?
...on script returns a boolean if a string is valid json:
import json
def is_json(myjson):
try:
json_object = json.loads(myjson)
except ValueError as e:
return False
return True
Which prints:
print is_json("{}") #prints True
print is_json("{asdf}") ...
How to spread django unit tests over multiple files?
...er valid from Django 1.6, see this post.
You can create tests folder with ___init___.py inside (so that it becomes a package). Then you add your split test .py files there and import all of them in ___init___.py.
I.e: Substitute the test.py file with a module that looks and acts like the file:
Cr...
How to rename with prefix/suffix?
...ly be short and simple for this. For example, to rename all *.jpg to prefix_*.jpg in the current directory:
for filename in *.jpg; do mv "$filename" "prefix_$filename"; done;
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Hash function that produces short hashes?
...ike the accepted answer):
import base64
import hashlib
import uuid
unique_id = uuid.uuid4()
# unique_id = UUID('8da617a7-0bd6-4cce-ae49-5d31f2a5a35f')
hash = hashlib.sha1(str(unique_id).encode("UTF-8"))
# hash.hexdigest() = '882efb0f24a03938e5898aa6b69df2038a2c3f0e'
result = base64.b64encode(has...