Tutorial by Examples: g

If you aren't sure whether a value is of the type you think it is, you can safely cast it using the as operator. If the value is not of that type, the resulting value will be null. object value = "-1"; int? number = value as int?; if(number != null) { Console.WriteLine(Math.Abs(nu...

A value will automatically be cast to the appropriate type if the compiler knows that it can always be converted to that type. int number = -1; object value = number; Console.WriteLine(value); In this example, we didn't need to use the typical explicit casting syntax because the compiler knows...

If you need to know whether a value's type extends or implements a given type, but you don't want to actually cast it as that type, you can use the is operator. if(value is int) { Console.WriteLine(value + "is an int"); }

In the most basic form, it is possible to select a single variable from a table by calling the object's get_var method passing in an SQL query. global $wpdb; $user = $wpdb->get_var( "SELECT ID FROM $wpdb->users WHERE user_email='[email protected]'" ); It is very important to note that...

public class Singleton { private static class InstanceHolder { static final Singleton INSTANCE = new Singleton(); } public static Singleton getInstance() { return InstanceHolder.INSTANCE; } private Singleton() {} } This initializes the INSTANCE vari...

Prerequisites The Windows version of Elasticsearch can be obtained from this link: https://www.elastic.co/downloads/elasticsearch. The latest stable release is always at the top. As we are installing on Windows, we need the .ZIP archive. Click the link in the Downloads: section and save the file t...

Getting all the information of current user in wordpress using the predefined function wp_get_current_user(); <?php $current_user = wp_get_current_user(); echo "Username :".$current_user->user_login; echo "Username :".$current_user-&g...

function social_profiles( $contactmethods ) { $contactmethods['facebook_profile'] = 'Facebook Profile URL'; $contactmethods['twitter_profile'] = 'Twitter Profile URL'; $contactmethods['google_profile'] = 'Google Profile URL'; $contactmethods['linkedin_profile'] = 'Li...

function remove_contact_methods( $contactmethods ) { unset($contactmethods['facebook_profile']); unset($contactmethods['twitter_profile']); return $contactmethods; } add_filter( 'user_contactmethods', 'remove_contact_methods', 10, 1);

To create a Grails application, use the grails create-app command. The following command creates a Grails application, named myapp in the current directory: grails create-app fancy-app Running it, is as simple as visiting the, newly created, application directory: cd fancy-app and then grai...

Package names Package names should be all lower case without underscores or other special characters. Package names begin with the reversed authority part of the web address of the company of the developer. This part can be followed a by project/program structure dependent package substructure. ...

The .split() method splits a string into an array of substrings. By default .split() will break the string into substrings on spaces (" "), which is equivalent to calling .split(" "). The parameter passed to .split() specifies the character, or the regular expression, to use for...

It is sometimes useful to verify that your work on Developer edition hasn't introduced a dependency on any features restricted to Enterprise edition. You can do this using the sys.dm_db_persisted_sku_features system view, like so: SELECT * FROM sys.dm_db_persisted_sku_features Against the datab...

generate sample DF In [39]: df = pd.DataFrame(np.random.randint(0, 10, size=(5, 6)), columns=['a10','a20','a25','b','c','d']) In [40]: df Out[40]: a10 a20 a25 b c d 0 2 3 7 5 4 7 1 3 1 5 7 2 6 2 7 4 9 0 8 7 3 5 8 8 9 6 8 4 8 1 ...

from datetime import datetime import pandas_datareader.data as wb stocklist = ['AAPL','GOOG','FB','AMZN','COP'] start = datetime(2016,6,8) end = datetime(2016,6,11) p = wb.DataReader(stocklist, 'yahoo',start,end) p - is a pandas panel, with which we can do funny things: let's see what...

import os import glob import pandas as pd def get_merged_csv(flist, **kwargs): return pd.concat([pd.read_csv(f, **kwargs) for f in flist], ignore_index=True) path = 'C:/Users/csvfiles' fmask = os.path.join(path, '*mask*.csv') df = get_merged_csv(glob.glob(fmask), index_col=None, use...

You can iterate on the object returned by groupby(). The iterator contains (Category, DataFrame) tuples. # Same example data as in the previous example. import numpy as np import pandas as pd np.random.seed(0) df = pd.DataFrame({'Age': np.random.randint(20, 70, 100), 'Sex':...

Imagine a goroutine with a two step process, where the main thread needs to do some work between each step: func main() { ch := make(chan struct{}) go func() { // Wait for main thread's signal to begin step one <-ch // Perform work time.Sle...

main.go: package main import ( "fmt" "io/ioutil" "log" "net/http" ) func fetchContent(url string) (string, error) { res, err := http.Get(url) if err != nil { return "", nil } defer res.Body.Clo...

extern crate serde; extern crate serde_json; #[macro_use] extern crate serde_derive; use std::collections::BTreeMap as Map; #[derive(Serialize)] struct Resource { // Always serialized. name: String, // Never serialized. #[serde(skip_serializing)] hash: String, ...