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MongoDB shell version v3.4.10
connecting to: mongodb://127.0.0.1:27017/m121
MongoDB server version: 3.4.10

Chapter 3 Lab Lookup Pipelines Performance Comparison


## start on air_alliances - using $filter

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# initialization file (not found)

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# Course Data Scientist - Exploratory Data Analysis - Course Project 1

# compare the different methods of reading in
# the file "household_power_consumption.txt" and
# subsetting Date to 1/2/2007 and 2/2/2007

library(data.table)
library(sqldf)
Sys.setlocale(category = "LC_MESSAGES", locale = "C") # english output of system.time

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# wk4 PA.R  R script for Prog Assign - week 4

# load the data set and create contigency table c
# for grouped petal width (col 4) and species col 5

fname <- 'wk4 dataset_390_1.txt'
colnames <- c('SL','SW','PL','PW','Species')
ds <- read.csv( fname, header = FALSE, sep = "\t", col.names=colnames)
breaks <- c(0.0, 0.5, 1.5, 2.0, 99.0)   # right border included
ds$PWc <- cut(ds$PW, breaks=breaks, right = TRUE)

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//
// reference: https://groups.google.com/forum/?fromgroups=&hl=pt-BR#!topic/mongodb-user/h2N5v8gwi6M
//
db.recip.drop();
db.recip.insert({_id:"B",i:[1,2,3,4,5,6]});
db.recip.insert({_id:"C",i:[1,2,3,6,9,8]});
db.recip.insert({_id:"D",i:[1,2,3]});

A = [1,2,3,4];
qry = {};

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/*
 convertAggregateResultToCollection (alias: carc)
 Author: Ronald Stalder <[email protected]>
*/

var convertAggregateResultToCollection = function (aggResult, options) {
    
    // void function to supress output
    var _v = function() {};
    

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// for mongo shell
// verify homework 3-1 without using aggregate (for Windows XP)
// "provide the identity of the student with the highest average in the class"

var maxAvg = 0;
var maxAvgId = 0;

// loop per student, calculate its' average and compare
var cursor = db.students.find();
while ( cursor.hasNext() ) {

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var mongodb = require('mongodb');
var _ = require('underscore');

var db = mongodb.Db('school', new mongodb.Server('localhost', 27017), {safe: true});

db.open(function(err, client) {
	if(err) {
		console.log('Error opening connection' + err);
	}
	console.log('db opened');

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var mongodb = require('mongodb');
var _ = require('underscore');

var db = mongodb.Db('students', new mongodb.Server('localhost', 27017), {safe: true});

db.open(function(err, client) {
	if(err) {
		console.log('Error opening connection' + err);
	}
	console.log('db opened');