There are several ways to format and get a string as a result.
The .NET way is by using String.Format or StringBuilder.AppendFormat:
open System
open System.Text
let hello = String.Format ("Hello {0}", "World")
// return a string with "Hello World"
let builder...
CLP(FD) constraints are provided by all serious Prolog implementations. They allow us to reason about integers in a pure way.
?- X #= 1 + 2.
X = 3.
?- 5 #= Y + 2.
Y = 3.
Sometimes you want to destructure key under a map which might not be present in the map, but you want a default value for the destructured value. You can do that this way:
(def my-map {:a 3 :b 4})
(let [{a :a
b :b
:keys [c d]
:or {a 1
c 2}} my-map]
(println ...
Destructurling works in many places, as well as in the param list of an fn:
(defn my-func [[_ a b]]
(+ a b))
(my-func [1 2 3]) ;= 5
(my-func (range 5)) ;= 3
Destructuring also works for the & rest construct in the param list:
(defn my-func2 [& [_ a b]]
(+ a b))
(my-func2 1 ...
Destructuring also gives you the ability to interpret a sequence as a map:
(def my-vec [:a 1 :b 2])
(def my-lst '("smthg else" :c 3 :d 4))
(let [[& {:keys [a b]}] my-vec
[s & {:keys [c d]} my-lst]
(+ a b c d)) ;= 10
It is useful for defining functions with named p...
CLP(FD) constraints are completely pure relations. They can be used in all directions for declarative integer arithmetic:
?- X #= 1+2.
X = 3.
?- 3 #= Y+2.
Y = 1.
Following code will release the lock. There will be no problem. Behind the scenes lock statement works as try finally
lock(locker)
{
throw new Exception();
}
More can be seen in the C# 5.0 Specification:
A lock statement of the form
lock (x) ...
where x is an expression of a referenc...
The function toupper will convert a string to upper case (capital letters). For example:
BEGIN {
greeting = "hello"
loud_greeting = toupper(greeting)
print loud_greeting
}
This code will output "HELLO" when run.
This example will show you how to create a simple animation using the canvas and the 2D context. It is assumed you know how to create and add a canvas to the DOM and obtain the context
// this example assumes ctx and canvas have been created
const textToDisplay = "This is an example that uses...
Pyinstaller is a normal python package. It can be installed using pip:
pip install pyinstaller
Installation in Windows
For Windows, pywin32 or pypiwin32 is a prerequisite. The latter is installed automatically when pyinstaller is installed using pip.
Installation in Mac OS X
PyInstaller works...
In the simplest use-case, just navigate to the directory your file is in, and type:
pyinstaller myfile.py
Pyinstaller analyzes the file and creates:
A myfile.spec file in the same directory as myfile.py
A build folder in the same directory as myfile.py
A dist folder in the same directory as m...
psql < backup.sql
A safer alternative uses -1 to wrap the restore in a transaction. The -f specifies the filename rather than using shell redirection.
psql -1f backup.sql
Custom format files must be restored using pg_restore with the -d option to specify the database:
pg_restore -d DATABA...
$ pg_dumpall -f backup.sql
This works behind the scenes by making multiple connections to the server once for each database and executing pg_dump on it.
Sometimes, you might be tempted to set this up as a cron job, so you want to see the date the backup was taken as part of the filename:
$ post...
The datetime module can convert a POSIX timestamp to a ITC datetime object.
The Epoch is January 1st, 1970 midnight.
import time
from datetime import datetime
seconds_since_epoch=time.time() #1469182681.709
utc_date=datetime.utcfromtimestamp(seconds_since_epoch) #datetime.datetime(2016, 7, 2...
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.
...
To convert NSString to const char use -[NSString UTF8String]:
NSString *myNSString = @"Some string";
const char *cString = [myNSString UTF8String];
You could also use -[NSString cStringUsingEncoding:] if your string is encoded with something other than UTF-8.
For the reverse path use...
Think about a situation where we need to callback a function with arguments.
std::function used with std::bind gives a very powerful design construct as shown below.
class A
{
public:
std::function<void(int, const std::string&)> m_CbFunc = nullptr;
void foo()
{
...
