jitter

0th

Percentile

‘Jitter’ (Add Noise) to Numbers

Add a small amount of noise to a numeric vector.

Keywords
utilities, dplot
Usage
jitter(x, factor = 1, amount = NULL)
Arguments
x

numeric vector to which jitter should be added.

factor

numeric.

amount

numeric; if positive, used as amount (see below), otherwise, if = 0 the default is factor * z/50.

Default (NULL): factor * d/5 where d is about the smallest difference between x values.

Details

The result, say r, is r <- x + runif(n, -a, a) where n <- length(x) and a is the amount argument (if specified).

Let z <- max(x) - min(x) (assuming the usual case). The amount a to be added is either provided as positive argument amount or otherwise computed from z, as follows:

If amount == 0, we set a <- factor * z/50 (same as S).

If amount is NULL (default), we set a <- factor * d/5 where d is the smallest difference between adjacent unique (apart from fuzz) x values.

Value

jitter(x, …) returns a numeric of the same length as x, but with an amount of noise added in order to break ties.

References

Chambers, J. M., Cleveland, W. S., Kleiner, B. and Tukey, P.A. (1983) Graphical Methods for Data Analysis. Wadsworth; figures 2.8, 4.22, 5.4.

Chambers, J. M. and Hastie, T. J. (1992) Statistical Models in S. Wadsworth & Brooks/Cole.

See Also

rug which you may want to combine with jitter.

Aliases
  • jitter
Examples
library(base) # NOT RUN { round(jitter(c(rep(1, 3), rep(1.2, 4), rep(3, 3))), 3) ## These two 'fail' with S-plus 3.x: jitter(rep(0, 7)) jitter(rep(10000, 5)) # }
Documentation reproduced from package base, version 3.6.1, License: Part of R 3.6.1

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