pretty printing

utils_print.R

# Code for formatting numbers (for my knitr docs)

library("magrittr")
library("dplyr", warn.conflicts = FALSE)
library("broom")
library("stringr")

# Fixed width integers (like for track or image numbers in filenames)
sprintf("%03.f", seq_len(20))
# [1] "001" "002" "003" "004" "005" "006" "007" "008" "009" "010"
#[11] "011" "012" "013" "014" "015" "016" "017" "018" "019" "020"



# p-values
model <- lm(Sepal.Length ~ Species * Sepal.Width, iris) %>% tidy %T>% print
#                            term  estimate std.error statistic      p.value
# 1                   (Intercept) 2.6390012 0.5715053 4.6176320 8.526118e-06
# 2             Speciesversicolor 0.9007335 0.7987512 1.1276772 2.613317e-01
# 3              Speciesvirginica 1.2678352 0.8161509 1.5534324 1.225149e-01
# 4                   Sepal.Width 0.6904897 0.1657268 4.1664328 5.311035e-05
# 5 Speciesversicolor:Sepal.Width 0.1745880 0.2598919 0.6717717 5.028054e-01
# 6  Speciesvirginica:Sepal.Width 0.2110448 0.2557557 0.8251811 4.106337e-01

# Print two digits of a p-value, but use the "< .001" notation on tiny values. 
format_pval <- function(ps, html = FALSE) {
  template <- ifelse(html, "&lt;&nbsp;.001", "< .001")
  ps_chr <- ps %>% 
    get_digits(2) %>%
    remove_leading_zero 
  ps_chr[ps < 0.001] <- template
  ps_chr
}

# Get n significant digits
get_digits <- function(xs, n = 2) { 
  formatC(xs, digits = n, format = "fg")
}

# Don't need a leading zero on bounded numbers like p-values
remove_leading_zero <- function(xs) {
  str_replace(xs, "^0", "")
}

model %>% 
  mutate(p = format_pval(p.value)) %>% 
  mutate_each(funs(round(., 2)), estimate:p.value)
#                            term estimate std.error statistic p.value      p
# 1                   (Intercept)     2.64      0.57      4.62    0.00 < .001
# 2             Speciesversicolor     0.90      0.80      1.13    0.26    .26
# 3              Speciesvirginica     1.27      0.82      1.55    0.12    .12
# 4                   Sepal.Width     0.69      0.17      4.17    0.00 < .001
# 5 Speciesversicolor:Sepal.Width     0.17      0.26      0.67    0.50     .5
# 6  Speciesvirginica:Sepal.Width     0.21      0.26      0.83    0.41    .41