Tutorial by Examples: am

There are a couple of ways to delete a column in a DataFrame. import numpy as np import pandas as pd np.random.seed(0) pd.DataFrame(np.random.randn(5, 6), columns=list('ABCDEF')) print(df) # Output: # A B C D E F # 0 -0.895467 0.386902...

Say we have an enum DayOfWeek: enum DayOfWeek { SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY; } An enum is compiled with a built-in static valueOf() method which can be used to lookup a constant by its name: String dayName = DayOfWeek.SUNDAY.name(); assert dayName.equal...

The following code will print the arguments to the program, and the code will attempt to convert each argument into a number (to a long): #include <stdlib.h> #include <stdio.h> #include <errno.h> #include <limits.h> int main(int argc, char* argv[]) { for (int ...

Python 2.x2.7 To import a module through a function call, use the importlib module (included in Python starting in version 2.7): import importlib random = importlib.import_module("random") The importlib.import_module() function will also import the submodule of a package directly: c...

If you are building a function that may be heavy on the processor (either clientside or serverside) you may want to consider a memoizer which is a cache of previous function executions and their returned values. This allows you to check if the parameters of a function were passed before. Remember, p...

A syntactic extension that lets you write \case in place of \arg -> case arg of. Consider the following function definition: dayOfTheWeek :: Int -> String dayOfTheWeek 0 = "Sunday" dayOfTheWeek 1 = "Monday" dayOfTheWeek 2 = "Tuesday" dayOfTheWeek 3 = "W...

Pass dynamic inventory to ansible-playbook: ansible-playbook -i inventory/dyn.py -l targethost my_playbook.yml python inventory/dyn.py should print out something like this: { "_meta": { "hostvars": { "10.1.0.10": { "ansible_user": ...

Inventory is the Ansible way to track all the systems in your infrastructure. Here is a simple inventory file containing a single system and the login credentials for Ansible. [targethost] 192.168.1.1 ansible_user=mrtuovinen ansible_ssh_pass=PassW0rd

To get basic information about a DataFrame including the column names and datatypes: import pandas as pd df = pd.DataFrame({'integers': [1, 2, 3], 'floats': [1.5, 2.5, 3], 'text': ['a', 'b', 'c'], 'ints with None': [1, None, 3]}) ...

df = pd.DataFrame({'old_name_1': [1, 2, 3], 'old_name_2': [5, 6, 7]}) print(df) # Output: # old_name_1 old_name_2 # 0 1 5 # 1 2 6 # 2 3 7 To rename one or more columns, pass the old names and new names as a dictionary: df.r...

df = pd.DataFrame({'a': [1, 2, 3], 'b': [4, 5, 6], 'c': [7, 8, 9]}) To list the column names in a DataFrame: >>> list(df) ['a', 'b', 'c'] This list comprehension method is especially useful when using the debugger: >>> [c for c in df] ['a', 'b', 'c'] This is the long w...

To start using Vue.js, make sure you have the script file included in your HTML. For example, add the following to your HTML. <script src="https://npmcdn.com/vue/dist/vue.js"></script> Simple Example HTML template <div id="app"> {{ message }} </div&...

If you want to support a url parameter more complex than an id number, you may run into trouble with the parser if the value contains a period. Anything following a period will be assumed to be a format (i.e. json, xml). You can work around this limitation by using a constraint to broaden the accep...

Swift func createCollectionView() { let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout() let collectionView = UICollectionView(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height), collectionViewLayout: layout) collectionView.dataSource = sel...

struct MetricDistance { var distanceInMeters: Double init(fromCentimeters centimeters: Double) { distanceInMeters = centimeters / 100 } init(fromKilometers kilos: Double) { distanceInMeters = kilos * 1000 } } let myDistance = MetricDistance(fromCentim...

A generic class with the type parameter Type class MyGenericClass<Type>{ var value: Type init(value: Type){ self.value = value } func getValue() -> Type{ return self.value } func setValue(value: Type){ self.value = value }...

Here's how you can destructure a map: (def my-map {:a 1 :b 2 :c 3}) Then, for example, within a let block you can extract values from the map very succinctly as follows: (let [{x :a y :c} my-map] (println ":a val:" x ", :c val: " y)) ;; :a val: 1 , :c val: 3 Notice th...

# For Python 2 compatibility. from __future__ import print_function import lxml.html import requests def main(): r = requests.get("https://httpbin.org") html_source = r.text root_element = lxml.html.fromstring(html_source) # Note root_element.xpath() gives a *...

Controllers have access to HTTP parameters (you might know them as ?name=foo in URLs, but Ruby on Rails handle different formats too!) and output different responses based on them. There isn't a way to distinguish between GET and POST parameters, but you shouldn't do that in any case. class UsersCo...

class UsersController < ApplicationController def index respond_to do |format| format.html do render html: "Hello #{ user_params[:name] } user_params[:sentence]" end end end private def user_params if params[:name] == "john&quo...