Partial application means calling a function with less arguments than it has and saving the result as another function (that waits for the rest of the arguments).
multiplyBy: Int -> Int -> Int
multiplyBy x y =
x * y
multiplyByTwo : Int -> Int -- one Int has disappeared! we ...
Sometimes, we may open a file which we do not have permission to write in Vim without using sudo.
Use this command to save a read-only file edited in Vim.
:w !sudo tee > /dev/null %
Which you could map to :w!! in your .vimrc:
cmap w!! w !sudo tee > /dev/null %
You will be presented a ...
Starter code to create and remove a full page canvas that responds to resize events via javascript.
var canvas; // Global canvas reference
var ctx; // Global 2D context reference
// Creates a canvas
function createCanvas () {
const canvas = document.createElement(&q...
Angular 2.0.0-rc.4
In this example we'll create a "Hello World!" app with only one root component (AppComponent) for the sake of simplicity.
Prerequisites:
Node.js v5 or later
npm v3 or later
Note: You can check versions by running node -v and npm -v in the console/terminal.
...
There are 4 methods for comparing NSDates in Objective-C:
- (BOOL)isEqualToDate:(NSDate *)anotherDate
- (NSDate *)earlierDate:(NSDate *)anotherDate
- (NSDate *)laterDate:(NSDate *)anotherDate
- (NSComparisonResult)compare:(NSDate *)anotherDate
Consider the following example using 2 dates, N...
Show the changes between the tip of new and the tip of original:
git diff original new # equivalent to original..new
Show all changes on new since it branched from original:
git diff original...new # equivalent to $(git merge-base original new)..new
Using only one parameter such as
...
Bash indirection permits to get the value of a variable whose name is contained in another variable. Variables example:
$ red="the color red"
$ green="the color green"
$ color=red
$ echo "${!color}"
the color red
$ color=green
$ echo "${!color}"
the ...
The semantics for this are similar to that of default value substitution, but instead of substituting a default value, it errors out with the provided error message. The forms are ${VARNAME?ERRMSG} and ${VARNAME:?ERRMSG}. The form with : will error our if the variable is unset or empty, whereas the ...
To create a JAR containing all of its dependencies, it is possible to use the built-in descriptor format jar-with-dependencies. The following example configures an execution of the Assembly Plugin bound to the package phase, using this built-in descriptor and declaring a main class of com.example:
...
Creates a image representing a linear gradient of colors.
linear-gradient( 0deg, red, yellow 50%, blue);
This creates a gradient going from bottom to top, with colors starting at red, then yellow at 50%, and finishing in blue.
The ternary operator can be thought of as an inline if statement. It consists of three parts. The operator, and two outcomes. The syntax is as follows:
$value = <operator> ? <true value> : <false value>
If the operator is evaluated as true, the value in the first block will be ...
import pandas as pd
df = pd.DataFrame(np.random.randn(5, 5), columns=list('ABCDE'))
To generate various summary statistics. For numeric values the number of non-NA/null values (count), the mean (mean), the standard deviation std and values known as the five-number summary :
min: minimum (smal...
<root xmlns="http://test/">
<element xmlns:example="http://foobar/">
<example:hello_world attribute="another example" />
</element>
</root>
The expression /root will return nothing, because there is no non-namespaced ...
Install jquery via npm :
npm install jquery --save
Install typings for the library:
To add typings for a library, do the following:
typings install jquery --global --save
Add jquery to angular-cli-build.js file to vendorNpmFiles array:
This is required so the build system...
You can search for man pages containing a particular string in their description using:
man -k <string>
For example:
man -k unzip
Might return:
man -k unzip
IO::Uncompress::Bunzip2(3pm) - Read bzip2 files/buffers
IO::Uncompress::Gunzip(3pm) - Read RFC 1952 files/buffers
IO::Uncom...
The default Angular router allows navigation to and from any route unconditionally. This is not always the desired behavior.
In a scenario where a user may conditionally be allowed to navigate to or from a route, a Route Guard may be used to restrict this behavior.
If your scenario fits one of the...
File main.ts (or boot.ts)
Consider the examples above:
Create the guard (where the Guard is created) and
Add guard to route configuration, (where the Guard is configured for route, then APP_ROUTER_PROVIDERS is exported),
we can couple the bootstrap to Guard as follows
import { bootstrap }...
You can use the ** keyword argument unpacking operator to deliver the key-value pairs in a dictionary into a function's arguments. A simplified example from the official documentation:
>>>
>>> def parrot(voltage, state, action):
... print("This parrot wouldn't", ac...
