Vector functions

The package adds the following vector functions

# count returns the number of non missing observation
count(c(NA, NA, 1), 1:3)
count(data_frame(c(NA, NA, 1), 1:3))

# sample_mode returns the statistical mode
sample_mode(c(1, 2, 2))
sample_mode(c(1, 2))
sample_mode(c(NA, NA, 1))
sample_mode(c(NA, NA, 1), na.rm = TRUE)

# pctile computes quantile and weighted quantile of type 2 (similarly to Stata _pctile)
v <- c(NA, 1:10)                   
pctile(v, probs = c(0.3, 0.7), na.rm = TRUE) 

# xtile creates integer variable for quantile categories (corresponds to Stata xtile)
v <- c(NA, 1:10)                   
xtile(v, n_quantiles = 3) # 3 groups based on terciles
xtile(v, probs = c(0.3, 0.7)) # 3 groups based on two quantiles
xtile(v, cutpoints = c(2, 3)) # 3 groups based on two cutpoints

# winsorize (default based on 5 x interquartile range)
v <- c(1:4, 99)
winsorize(v)
winsorize(v, replace = NA)
winsorize(v, probs = c(0.01, 0.99))
winsorize(v, cutpoints = c(1, 50))