mpettis

#' ---
#' title: "Beer example"
#' author: "Matt Pettis (matthew.pettis@gmail.com)"
#' date: "`r Sys.Date()`"
#' output:
#'   html_document:
#'     toc: true
#'     toc_depth: 3
#'     code_folding: show
#' editor_options:

mpettis

library(lubridate)
library(tidyverse)

seq(
    from=as.POSIXct("2012-1-1 0:00", tz="UTC"),
    to=as.POSIXct("2012-1-3 23:00", tz="UTC"),
    by="hour"
) ->
    dt

mpettis

library(tidyverse)
library(broom)

US <- read_csv("https://raw.githubusercontent.com/nytimes/covid-19-data/master/us.csv") %>%
  mutate(new_deaths = deaths - lag(deaths)) %>%
  filter(date >= "2020-02-26")

models <- tibble(degrees = 2:4) %>%
  mutate(model = map(degrees, ~ lm(log(new_deaths + 1) ~ poly(date, .), data = US)))

mpettis

## Using run-length-encoding, create groups of identical values and put that
## common grouping identifier into a `grp` column.
library(tidyverse)

set.seed(42)

df <- tibble(x = sample(c(0,1), size=20, replace=TRUE, prob = c(0.2, 0.8)))

df %>%
    mutate(grp = rle(x)$lengths %>% {rep(seq(length(.)), .)})

mpettis

---
title: "spread-group-percent"
author: "Matt Pettis"
date: "March 22, 2019"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

mpettis

library(geosphere)
library(tidyverse)

# Simple dataframe and use case:
ref_ll <- c(-95.0, 45.0)

df__ <- tribble(
   ~lon,  ~lat,
   -95.0, 45.0,
   -96.0, 45.0,

mpettis

################################################################################
# Make a function that does what I want
# Take a dataframe, identify the target column with runs, ID the index column,
# which is the column that I want to capture the first and last values of for
# runs.


#' rle_as_df
#' 
#' Turn run-length encoding into a dataframe so it can be used with ggplot/geom_area.

mpettis

# Dealing with NULLs as list values

library(tidyverse)

# As advertised on the tin:
is.null(NULL)
#> [1] TRUE

# is.null() is not vectorized?
is.null(list(NULL))

mpettis

``` r
## 'or'ing together same-length vectors of booleans.
## use case is to set up sets of booleans that have the same length and should
## be all 'or'ed together to form a condition.

# Base R way:
lstt <- list(
    a = c(T, F, F, F)
    , b = c(F, T, F, F)
    , c = c(F, F, T, F)

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