mpettis

• Introduction
  • Standard Evaluation escape hatches
• Examples
  • Selecting columns
  • Creating summarized computed columns
  • Non-dplyr examples with formulas
• [Using dplyr when discovering columns in a data

mpettis

#!/usr/bin/env Rscript

#library(plyr)
library(dplyr)
library(lubridate)



  ## Datetimes, 15min increments, that span DST breaks
dt_str <- c(

mpettis

• Description

• Config

• Data

• Modeling

  knitr::opts_chunk$set(echo = TRUE, fig.width=12, fig.height=9, warnings=FALSE) options(width=116)

Description

mpettis

• Introduction
• Setup
• Datetime formats
  • Formatting dates
  • Parsing datetimes
  • Internal structures, briefly
• Timezones
  • Quick quiz
  • Basics, and brief overview
• [What is a timezone, and what

mpettis

• Introduction
• Setup
• plyr
  • A quick map
  • a.ply functions
    • a_ply
    • aaply
    • alply
    • adply
• Multi-dimensional arrays

mpettis

• Introduction
• Setup
• Datetime formats
  • Formatting dates
  • Parsing datetimes
  • Internal structures, briefly
• Timezones
  • Quick quiz
  • Basics, and brief overview
• [What is a timezone, and what

mpettis

• Introduction
• Dataset to work with
  • What are the total number of observations made?
• Reveiw and such
  • How does 'mean' work?
• Base functions for summarization
  • tapply
• by

mpettis

## This is just a quick exploration, answering the question:
## How do I reconstruct a signal by picking the highest-power frequency from a periodogram?
## Assumes I keep the constant (DC) term.
## -----------------------------------------------------------------------------
## Fourier decomposition exploration
## -----------------------------------------------------------------------------

x <- 10 * sin(2 * pi * (1:75) / 25) + 300 + rnorm(1:75, 0, 2.5)
x

mpettis

Very procedural code, but works.  If I have a set of time intervals (lubridate intervals), and I want to consolidate any chain of overlapping intervals into a single interval with left end the min of all start times and right side as max of all end times, this is the code to do that.

``` r
## Consolidating intervals

suppressPackageStartupMessages(library(dplyr))
suppressPackageStartupMessages(library(lubridate))

# In this table of intervals, rows 3,4, and 5 form a chain of intervals.  They should be rolled into 1 interval.
# And note rows 3 and 5 do not themselves overlap, but they are chained together by having overlap with row 4.

mpettis

---
title: "R-user-group_tidyr-talk"
author: "Matt Pettis"
date: "November 22, 2017"
always_allow_html: yes
output:
  html_document:
    toc: true
---