Tom Hopper tomhopper

Michigan, United States

Recently created

Least recently created

Recently updated

Least recently updated

tomhopper / addNewData.R

Created October 9, 2016 00:12 — forked from dfalster/addNewData.R

The function addNewData.R modifies a data frame with a lookup table. This is useful where you want to supplement data loaded from file with other data, e.g. to add details, change treatment names, or similar. The function readNewData is also included. This function runs some checks on the new table to ensure it has correct variable names and val…

	##' Modifies 'data' by adding new values supplied in newDataFileName
	##'
	##' newDataFileName is expected to have columns
	##' c(lookupVariable,lookupValue,newVariable,newValue,source)
	##'
	##' Within the column 'newVariable', replace values that
	##' match 'lookupValue' within column 'lookupVariable' with the value
	##' newValue'. If 'lookupVariable' is NA, then replace all elements
	##' of 'newVariable' with the value 'newValue'.
	##'

tomhopper / dplyr_filter_ungroup.R

Created January 29, 2016 20:31 — forked from jhofman/dplyr_filter_ungroup.R

careful when filtering with many groups in dplyr

	library(dplyr)

	# create a dummy dataframe with 100,000 groups and 1,000,000 rows
	# and partition by group_id
	df <- data.frame(group_id=sample(1:1e5, 1e6, replace=T),
	val=sample(1:100, 1e6, replace=T)) %>%
	group_by(group_id)

	# filter rows with a value of 1 naively
	system.time(df %>% filter(val == 1))

tomhopper / random_word_vector.R

Last active August 29, 2015 14:17 — forked from anonymous/random_word_vector.R

	# Create 2 replicates of 5 "words" generated from random characters,
	# each "word" 5 - 15 characters long, with word length following a
	# poisson distribution.
	rep(replicate(5, paste(sample(letters, round(rpois(5000, lambda = 3)+5, 0), replace = FALSE), collapse = "")), 2)

	# Sample output:
	# [1] "rfexnwyjst" "vwtadhjnly" "ztfgvldo" "tmerol" "mcqhosap" "rfexnwyjst" "vwtadhjnly" "ztfgvldo" "tmerol"
	#[10] "mcqhosap"