mpettis

library(tidyverse)
library(jsonlite)
#> 
#> Attaching package: 'jsonlite'
#> The following object is masked from 'package:purrr':
#> 
#>     flatten

# Ref: https://stackoverflow.com/questions/7944809/assigning-null-to-a-list-element-in-r

mpettis

# Ref: https://jennybc.github.io/purrr-tutorial/ls02_map-extraction-advanced.html#list_inside_a_data_frame
# Ref: https://github.com/tidyverse/tidyr/issues/22

suppressPackageStartupMessages(library(dplyr))
suppressPackageStartupMessages(library(purrr))

# Make iris dataset into list of data frames split by `Species`.
my_list <- split(iris, iris$Species)
str(my_list)
#> List of 3

mpettis

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

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

## 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

• 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

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

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• 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

• 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