Every package requires a setup.py file which describes the package.
Consider the following directory structure for a simple package:
+-- package_name
| |
| +-- __init__.py
|
+-- setup.py
The __init__.py contains only the line def foo(): return 100.
The following setup.py...
docopt turns command-line argument parsing on its head. Instead of parsing the arguments, you just write the usage string for your program, and docopt parses the usage string and uses it to extract the command line arguments.
"""
Usage:
script_name.py [-a] [-b] <path>
...
Comparing sets
In R, a vector may contain duplicated elements:
v = "A"
w = c("A", "A")
However, a set contains only one copy of each element. R treats a vector like a set by taking only its distinct elements, so the two vectors above are regarded as the same:
set...
The %in% operator compares a vector with a set.
v = "A"
w = c("A", "A")
w %in% v
# TRUE TRUE
v %in% w
# TRUE
Each element on the left is treated individually and tested for membership in the set associated with the vector on the right (consisting of all its...
To find every vector of the form (x, y) where x is drawn from vector X and y from Y, we use expand.grid:
X = c(1, 1, 2)
Y = c(4, 5)
expand.grid(X, Y)
# Var1 Var2
# 1 1 4
# 2 1 4
# 3 2 4
# 4 1 5
# 5 1 5
# 6 2 5
The result is a data.frame with one...
unique drops duplicates so that each element in the result is unique (only appears once):
x = c(2, 1, 1, 2, 1)
unique(x)
# 2 1
Values are returned in the order they first appeared.
duplicated tags each duplicated element:
duplicated(x)
# FALSE FALSE TRUE TRUE TRUE
anyDuplicated(x) >...
To count how many elements of two sets overlap, one could write a custom function:
xtab_set <- function(A, B){
both <- union(A, B)
inA <- both %in% A
inB <- both %in% B
return(table(inA, inB))
}
A = 1:20
B = 10:30
xtab_set(A, B)
# inB
...
Imagine you have the following HTML:
<div>
<label>Name:</label>
John Smith
</div>
And you need to locate the text "John Smith" after the label element.
In this case, you can locate the label element by text and then use .next_sibling property:
from ...
BeautifulSoup has a limited support for CSS selectors, but covers most commonly used ones. Use select() method to find multiple elements and select_one() to find a single element.
Basic example:
from bs4 import BeautifulSoup
data = """
<ul>
<li class="item&quo...
Sets are unordered collections of distinct elements. But sometimes we want to work with unordered collections of elements that are not necessarily distinct and keep track of the elements' multiplicities.
Consider this example:
>>> setA = {'a','b','b','c'}
>>> setA
set(['a', 'c'...
You can restrict the valid types used in a generic class by bounding that type in the class definition. Given the following simple type hierarchy:
public abstract class Animal {
public abstract String getSound();
}
public class Cat extends Animal {
public String getSound() {
...
Sometimes it's necessary to be able to extract values from an object using only references (ie. without transferring ownership).
struct Token {
pub id: u32
}
struct User {
pub token: Option<Token>
}
fn main() {
// Create a user with an arbitrary token
let user = User...
Let's say we have the following data:
>>> data = {"cats": [{"name": "Tubbs", "color": "white"}, {"name": "Pepper", "color": "black"}]}
Just dumping this as JSON does not do anything special here:
...
Light Table is a good editor to learn, experiment and run Clojure projects.
You can also run lein/boot projects by opening project.clj file. It will load all project dependencies.
It supports inline evalution, plugins and much more, so there's no need to add print statements and check the output i...
All built-in Clojure collections are immutable and heterogeneous, have literal syntax, and support the conj, count, and seq functions.
conj returns a new collection that is equivalent to an existing collection with an item "added", in either "constant" or logarithmic time. Wha...
A list is denoted by parentheses:
()
;;=> ()
A Clojure list is a singly linked list. conj "conjoins" a new element to the collection in the most efficient location. For lists, this is at the beginning:
(conj () :foo)
;;=> (:foo)
(conj (conj () :bar) :foo)
;;=> (:foo :ba...
For if you have to fine-tune what is published.
import { Mongo } from 'meteor/mongo';
import { Meteor } from 'meteor/meteor';
import { Random } from 'meteor/random';
if (Meteor.isClient) {
// established this collection on the client only.
// a name is required (first parameter) and this...
On the server, you can create a publication like this. this.userId is the id of the user who is currently logged in. If no user is logged in, you might want to throw an error and respond to it.
import Secrets from '/imports/collections/Secrets';
Meteor.publish('protected_data', function () {
...
