aammd

library(rvest)
st_tab <- read_html("https://en.wikipedia.org/wiki/List_of_Star_Trek_characters") %>%
  html_nodes(".wikitable td , .wikitable th") %>%
  html_text()

library(stringr)
titles <- st_tab %>%
  str_detect(regex("^\\n.*\\n$", perl = TRUE))

st_tab[titles]

aammd

has_decimal <- function(x){ (x - floor(x)) > 0 }

## from ?is.integer 
is.wholenumber <-
    function(x, tol = .Machine$double.eps^0.5)  abs(x - round(x)) < tol

## from http://stackoverflow.com/questions/3476782/how-to-check-if-the-number-is-integer/3477158#3477158

## from SO and also twitter https://twitter.com/polesasunder/status/700091075269005313
is_whole <- function(x) x%%1==0

aammd

library(dplyr)

d <- data_frame(A =c(rep("a", 5), rep("c",2)))
d

## one way to do it

d %>% 
  group_by(A) %>% 
  filter(length(A) > 2)

aammd

library(dplyr)
library(tidyr)
library(ggplot2)

df <- data_frame(x = rnorm(n = 20, mean = 4),
                 y = rnorm(n = 20, mean = 7)) %>% 
  gather(XY, numbers)

ggplot(df, aes(x = XY, y = numbers)) + 
  geom_point(position = position_jitter(width = 0.05)) +

aammd

library(purrr)
library(gapminder)

gapminder %>% 
  transpose %>% 
  map(~ splice(., totalgdp = .$pop * .$gdpPercap)) %>% 
  transpose %>% 
  simplify_all() %>% 
  as.data.frame() %>% 
  head

aammd

library(purrr)
library(gapminder)

gapminder %>% 
  transpose %>% 
  map(~ splice(., totalgdp = .$pop * .$gdpPercap)) %>% 
  transpose %>% 
  simplify_all() %>% 
  as.data.frame() %>% 
  head

aammd

aammd

aammd

aammd

library(dplyr)
library(ggplot2)

dat <- data_frame(xs = runif(10, 2, 15), 
                  ys = runif(10, 2, 15),
                  xe = rnorm(10, 2, 0.4),
                  ye = rnorm(10, 2, 0.4))


dat %>%