jeffhuangtw

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jeffhuangtw

As a Java developer, 

Please learn:

1. Core Java Mastery
- OOP principles (SOLID, DRY, KISS)
- Generics, Lambda expressions, Functional interfaces
- Java Streams API (map/reduce, collectors)
- Java Collections framework
- Java Reflection API

jeffhuangtw

<manifest>
    <!-- Request legacy Bluetooth permissions on older devices. -->
    <uses-permission android:name="android.permission.BLUETOOTH"
                     android:maxSdkVersion="30" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"
                     android:maxSdkVersion="30" />

    <!-- Needed only if your app looks for Bluetooth devices.
         You must add an attribute to this permission, or declare the
         ACCESS_FINE_LOCATION permission, depending on the results when you

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########## Install NGINX ##############

# Install software-properties-common package to give us add-apt-repository package
sudo apt-get install -y software-properties-common

# Install latest nginx version from community maintained ppa
sudo add-apt-repository ppa:nginx/stable

# Update packages after adding ppa

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// Sample: download json as excel file (BOM + utf-16le encoding)
// reference: 
// https://gist.github.com/maciejjankowski/2db91642fb9eaa771111f2c0538e4560
// 
<script>
function JSON2CSV(objArray) {
    var array = typeof objArray != 'object' ? JSON.parse(objArray) : objArray;
    var str = '';
    var line = '';
    // header

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const admin = require("admin");
function getFirebaseUser(req, res, next) {
  console.log("Check if request is authorized with Firebase ID token");

  if (
    !req.headers.authorization ||
    !req.headers.authorization.startsWith("Bearer ")
  ) {
    console.error(
      "No Firebase ID token was passed as a Bearer token in the Authorization header.",

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// 1. add a executable dev.sh to run your script (example: web.js)
#!/bin/bash
node --inspect web.js

// 2. install foreman
$ npm install -g foreman

// 3. prepare your environment variables file
$ touch .env

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// Google Play API Key
// ref: http://stackoverflow.com/questions/35127086/android-inapp-purchase-receipt-validation-google-play
// ref: https://developers.google.com/android-publisher/authorization
// ref: http://google.github.io/google-api-nodejs-client/18.0.0/index.html#toc14__anchor
//
// install npm package
// ref: https://github.com/google/google-api-nodejs-client
// $ npm install googleapis --save
//
const google = require('googleapis');

jeffhuangtw

Coursera course
https://www.coursera.org/learn/machine-learning

Week 1 Note:
Partial derivative in gradient descent for two variables
https://math.stackexchange.com/questions/70728/partial-derivative-in-gradient-descent-for-two-variables/189792#189792

Gradient descent
https://www.youtube.com/watch?v=WnqQrPNYz5Q&ab_channel=AlexanderIhler

jeffhuangtw

// resend verify email
Parse.Cloud.define("ResendVerifyEmail", function(request, response) {
    var user = Parse.User.current();
    if (!user) {
        response.error("INVALID_USER");
        return;
    }
    var email = request.params.email;
    var query = new Parse.Query(Parse.User);
    Parse.Cloud.useMasterKey();