Tutorial by Examples: f

<workflow-app xmlns="uri:oozie:workflow:0.4" name="shell-wf"> <start to="shell-node"/> <action name="shell-node"> <shell xmlns="uri:oozie:shell-action:0.2"> <job-tracker>${jobTracker}</job-tracker> <name-n...

Table/Column Names Two common ways of formatting table/column names are CamelCase and snake_case: SELECT FirstName, LastName FROM Employees WHERE Salary > 500; SELECT first_name, last_name FROM employees WHERE salary > 500; Names should describe what is stored in their object. Th...

Content of file.json (one JSON object per line): {"A": 1, "B": 2} {"A": 3, "B": 4} How to read directly from a local file: pd.read_json('file.json', lines=True) # Output: # A B # 0 1 2 # 1 3 4

$man <command> Displays the on-line manual pages for the command $clear Clears the terminal screen $pwd Returns the working directory name $echo <string> Writes the string to the standard output $printf <string> Format and print the string Example: print $PATH ...

One of the most common and useful ways to replace text with regex is by using Capture Groups. Or even a Named Capture Group, as a reference to store, or replace the data. There are two terms pretty look alike in regex's docs, so it may be important to never mix-up Substitutions (i.e. $1) with Back...

I am using eclipse here, and you need to add below given dependency to your pom.xml 1.) POM.XML <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://m...

dplyr uses Non-Standard Evaluation(NSE), which is why we normally can use the variable names without quotes. However, sometimes during the data pipeline, we need to get our variable names from other sources such as a Shiny selection box. In case of functions like select, we can just use select_ to u...

CSRF stands for cross-site request forgery. You can prevent this attack by enabling an option in the application/config/config.php file as shown below. $config['csrf_protection'] = TRUE; When you create a form using the form_open() function, it will automatically insert a CSRF token in a hidden ...

// XSS Filtering $data = array( 'name'=> '<script>Abuse Data</script>' ); $data = $this->security->xss_clean($data); // Clean Data // Escaping Queries <?php $username = $this->input->post('username'); $query = 'SELECT * FROM subscribers_tbl ...

<?php // Setting parameters $time = time(); $values = [7, $time, $time]; // Prints "At 3:50:31 PM on Apr 19, 2015, there was a disturbance on planet 7." $pattern = "At {1, time} on {1, date}, there was a disturbance on planet {0, number}."; $formatter = new Messa...

import com.ibm.icu.text.MessageFormat import java.util.Locale import scala.collection.JavaConverters._ // Outputs "A common message for all options. Selected: (other)" val formatted = new MessageFormat( "{messageCount, plural, one {{aMessage} (one)} other {{aMessage} (othe...

With OptionsParser, it's really easy to set up default values. Just pre-populate the hash you store the options in: options = { :directory => ENV['HOME'] } When you define the parser, it will overwrite the default if a user provide a value: OptionParser.new do |opts| opts.on("-d&...

The splat operator removes individual elements of an array and makes them into a list. This is most commonly used to create a method that accepts a variable number of arguments: # First parameter is the subject and the following parameters are their spouses def print_spouses(person, *spouses) s...

When you have an ajax call, it's extremely difficult to get a log from inside of the callback function. But if you enable the debugging define('WP_DEBUG', true); and then after that add ini_set('log_errors',TRUE); ini_set('error_reporting', E_ALL); ini_set('error_log', dirname(__FILE__) . '/e...

By setting Multi-Release: true in the MANIFEST.MF file, the Jar file becomes a multi-release Jar and the Java runtime (as long as it supports the MRJAR format) will pick the appropriate versions of classes depending on the current major version. The structure of such a Jar is the following: jar ro...

Given the following multi-release Jar: jar root - demo - SampleClass.class - META-INF - versions - 9 - demo - SampleClass.class The following class prints the URL of the SampleClass: package demo; import java.net.URL; public class Main...

The following prints all stack frames of the current thread: 1 package test; 2 3 import java.lang.StackWalker.StackFrame; 4 import java.lang.reflect.InvocationTargetException; 5 import java.lang.reflect.Method; 6 import java.util.List; 7 import java.util.stream.Collectors; 8 9 pu...

A couple of other options allow stack traces to include implementation and/or reflection frames. This may be useful for debugging purposes. For instance, we can add the SHOW_REFLECT_FRAMES option to the StackWalker instance upon creation, so that the frames for the reflective methods are printed as ...

Table ORDERS +---------+------------+----------+-------+--------+ | orderid | customerid | customer | total | items | +---------+------------+----------+-------+--------+ | 1 | 1 | Bob | 1300 | 10 | | 2 | 3 | Fred | 500 | 2 | | 3 | ...

hadoop fs -setfacl