Functions

library("tidyverse")

## -- Attaching packages --------------------------------------- tidyverse 1.3.0 --

## v ggplot2 3.3.3     v purrr   0.3.4
## v tibble  3.1.0     v dplyr   1.0.5
## v tidyr   1.1.3     v stringr 1.4.0
## v readr   1.4.0     v forcats 0.5.1

## -- Conflicts ------------------------------------------ tidyverse_conflicts() --
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()

library("lubridate")

## 
## Attaching package: 'lubridate'

## The following objects are masked from 'package:base':
## 
##     date, intersect, setdiff, union

rescale01 <- function(x) {
  rng <- range(x, na.rm = TRUE, finite = TRUE)
  (x - rng[1]) / (rng[2] - rng[1])
}
rescale01_alt <- function(x, na.rm = FALSE) {
  rng <- range(x, na.rm = na.rm, finite = TRUE)
  (x - rng[1]) / (rng[2] - rng[1])
}
rescale01_alt(c(NA, 1:5), na.rm = FALSE)

## [1]   NA 0.00 0.25 0.50 0.75 1.00

#> [1]   NA 0.00 0.25 0.50 0.75 1.00
rescale01_alt(c(NA, 1:5), na.rm = TRUE)

## [1]   NA 0.00 0.25 0.50 0.75 1.00

#> [1]   NA 0.00 0.25 0.50 0.75 1.00
rescale01_alt2 <- function(x, na.rm = FALSE, finite = FALSE) {
  rng <- range(x, na.rm = na.rm, finite = finite)
  (x - rng[1]) / (rng[2] - rng[1])
}
rescale01_alt2(c(NA, 1:5), na.rm = FALSE, finite = FALSE)

## [1] NA NA NA NA NA NA

rescale01 <- function(x) {
  rng <- range(x, na.rm = TRUE, finite = TRUE)
  y <- (x - rng[1]) / (rng[2] - rng[1])
  y[y == -Inf] <- 0
  y[y == Inf] <- 1
  y
}
f1 <- function(string, prefix) {
  substr(string, 1, nchar(prefix)) == prefix
}

f2 <- function(x) {
  if (length(x) <= 1) return(NULL)
  x[-length(x)]
}

f3 <- function(x, y) {
  rep(y, length.out = length(x))
}
f1(c("abc", "abcde", "ad"), "ab")

## [1]  TRUE  TRUE FALSE

f2(1:3)

## [1] 1 2

f2(1:2)

## [1] 1

f2(1)

## NULL

f3(1:3, 4)

## [1] 4 4 4