R Code Snippets

Table of Contents

R Code Snippets

Grouping and counting objects

Using table

df <- data.frame(name = c("a", "a", "a", "b", "b", "c", "c", "c", "c"), x = 1:9)
tt <- table(df$name)
tt

a b c 
3 2 4 

Using dplyr

library(dplyr)
df <- data.frame(name = c("a", "a", "a", "b", "b", "c", "c", "c", "c"), x = 1:9)     
tt <- df %>% group_by(name) %>% summarize( count = n() )
tt
# A tibble: 3 × 2
    name count
  <fctr> <int>
1      a     3
2      b     2
3      c     4

ggplot2

Adding labels in a multi-faceted graph

I originally wrote this code to answer a question on Stackoverflow. Another user was quicker than me (and provided a more beautiful answer) but I want to save my version.

df <- data.frame(
x2=rnorm(100),
y2=rnorm(100), 
type = c(rep("type a", 50), 
         rep("type b", 50)), 
kind = rep(LETTERS[1:5],10))

library(ggplot2)
library(plyr)

quadrant_labels <- function(dat) {
  group_size = nrow(dat)
  lq1 <- nrow( subset( dat, x2 >= 0 & y2 >= 0))
  lq2 <- nrow( subset( dat, x2 >= 0 & y2  < 0))
  lq3 <- nrow( subset( dat, x2  < 0 & y2  < 0))
  lq4 <- nrow( subset( dat, x2  < 0 & y2 >= 0))
  data.frame(quadrant1 = lq1 / group_size,
             quadrant2 = lq2 / group_size, 
             quadrant3 = lq3 / group_size,
             quadrant4 = lq4 / group_size )  
}

labels <- ddply(df, c("type", "kind"), quadrant_labels)

ggplot(df, aes(x2, y2)) + geom_point() +
  geom_vline(xintercept = 0) +
  geom_hline(yintercept = 0) +
  geom_text(data = labels, x =  1, y =  1, aes(label = quadrant1), alpha=.40, size=5) +
  geom_text(data = labels, x =  1, y = -1, aes(label = quadrant2), alpha=.40, size=5) +
  geom_text(data = labels, x = -1, y = -1, aes(label = quadrant3), alpha=.40, size=5) +
  geom_text(data = labels, x = -1, y =  1, aes(label = quadrant4), alpha=.40, size=5) +
  facet_grid(type~kind)

multi-facets-labels.png

Date: 2017-02-16 gio 00:00

Author: Stefano Rodighiero

Created: 2017-07-11 mar 18:10

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