Tutorial by Examples: n

setTimeout Executes a function, after waiting a specified number of milliseconds. used to delay the execution of a function. Syntax : setTimeout(function, milliseconds) or window.setTimeout(function, milliseconds) Example : This example outputs "hello" to the console after 1 secon...

import pandas as pd df = pd.DataFrame({'Sex': ['M', 'M', 'F', 'M', 'F', 'F', 'M', 'M', 'F', 'F'], 'Age': [20, 19, 17, 35, 22, 22, 12, 15, 17, 22], 'Heart Disease': ['Y', 'N', 'Y', 'N', 'N', 'Y', 'N', 'Y', 'N', 'Y']}) df Age Heart Disease Sex 0 20 ...

Responses can be written to a http.ResponseWriter using templates in Go. This proves as a handy tool if you wish to create dynamic pages. (To learn how Templates work in Go, please visit the Go Templates Documentation page.) Continuing with a simple example to utilise the html/template to respond ...

Normal types, like String, are not nullable. To make them able to hold null values, you have to explicitly denote that by putting a ? behind them: String? var string : String = "Hello World!" var nullableString: String? = null string = nullableString // Compiler error: Can't...

In order to install PostgreSQL on OSX, you need to know which versions are currently supported. Use this command to see what versions you have available. sudo port list | grep "^postgresql[[:digit:]]\{2\}[[:space:]]" You should get a list that looks something like the following: post...

Ruby Standard Library has a Singleton module which implements the Singleton pattern. The first step in creating a Singleton class is to require and include the Singleton module in a class: require 'singleton' class Logger include Singleton end If you try to instantiate this class as you n...

When working with regular expressions one modifier for PCRE is g for global match. In R matching and replacement functions have two version: first match and global match: sub(pattern,replacement,text) will replace the first occurrence of pattern by replacement in text gsub(pattern,replace...

class Person { public string FirstName { get; set; } public string LastName { get; set; } } class Pet { public string Name { get; set; } public Person Owner { get; set; } } public static void Main(string[] args) { var magnus = new Person { FirstName = "Magnus...

The unary plus (+) precedes its operand and evaluates to its operand. It attempts to convert the operand to a number, if it isn't already. Syntax: +expression Returns: a Number. Description The unary plus (+) operator is the fastest (and preferred) method of converting something into a n...

The unary negation (-) precedes its operand and negates it, after trying to convert it to number. Syntax: -expression Returns: a Number. Description The unary negation (-) can convert the same types / values as the unary plus (+) operator can. Values that can't be converted will evaluat...

The bitwise NOT (~) performs a NOT operation on each bit in a value. Syntax: ~expression Returns: a Number. Description The truth table for the NOT operation is: aNOT a01101337 (base 10) = 0000010100111001 (base 2) ~1337 (base 10) = 1111101011000110 (base 2) = -1338 (base 10) A bit...

The logical NOT (!) operator performs logical negation on an expression. Syntax: !expression Returns: a Boolean. Description The logical NOT (!) operator performs logical negation on an expression. Boolean values simply get inverted: !true === false and !false === true. Non-boolean val...

DynamoDB is a fully managed service provided by AWS. It does not need to be installed or configured. AWS is responsible for all administrative burdens of operating, scalling and backup/restore of the distributed database.

dc is one of the oldest language on Unix. It is using the reverse polish notation, which means that you are first stacking numbers, then operations. For example 1+1 is written as 1 1+. To print an element from the top of the stack use command p echo '2 3 + p' | dc 5 or dc <<< '2 3...

It's often useful to combine multiple plot types in one graph (for example a Barplot next to a Scatterplot.) R makes this easy with the help of the functions par() and layout(). par() par uses the arguments mfrow or mfcol to create a matrix of nrows and ncols c(nrows, ncols) which will serve as a ...

All DATEs have a time component; however, it is customary to store dates which do not need to include time information with the hours/minutes/seconds set to zero (i.e. midnight). Use an ANSI DATE literal (using ISO 8601 Date format): SELECT DATE '2000-01-01' FROM DUAL; Convert it from a string ...

Convert it from a string literal using TO_DATE(): SELECT TO_DATE( '2000-01-01 12:00:00', 'YYYY-MM-DD HH24:MI:SS' ) FROM DUAL; Or use a TIMESTAMP literal: CREATE TABLE date_table( date_value DATE ); INSERT INTO date_table ( date_value ) VALUES ( TIMESTAMP '2000-01-01 12:00:00' ); Oracl...

Use TO_CHAR( date [, format_model [, nls_params]] ): (Note: if a format model is not provided then the NLS_DATE_FORMAT session parameter will be used as the default format model; this can be different for every session so should not be relied on. It is good practice to always specify the format mod...

When Oracle implicitly converts from a DATE to a string or vice-versa (or when TO_CHAR() or TO_DATE() are explicitly called without a format model) the NLS_DATE_FORMAT session parameter will be used as the format model in the conversion. If the literal does not match the format model then an excepti...

When SQL/Plus or SQL Developer display dates they will perform an implicit conversion to a string using the default date format model (see the Setting the Default Date Format Model example). You can change how a date is displayed by changing the NLS_DATE_FORMAT parameter.