matchWithPpm: Match values allowing a certain difference in ppm

In michaelwitting/CompoundDb: Creating and using (Chemical) Compound Annotation Databases

Description

Match numeric values in x against values in y and return indices of all matches of x in y allowing differences between the values specified with parameter ppm (part per million).

Usage

matchWithPpm(x, y, ppm = 0)

Arguments

x	numeric with input values to match in y. Supposed to be a shorter numeric than y.
y	numeric with values to match x against.
ppm	numeric(1) defining the allowed difference between values to be still considered a match. Differences smaller than +/- ppm are accepted.

Value

list with integer representing the index in y where each element in x matches (given the provided ppm).

Author(s)

Johannes Rainer

Examples

yvals <- abs(rnorm(1000))
yvals[123] <- yvals[2] - yvals[2] * 10 * 1e-6
yvals[124] <- yvals[2] + yvals[2] * 10 * 1e-6
yvals[125] <- yvals[2] + yvals[2] * 12 * 1e-6
xvals <- yvals[c(2, 3, 3, 20, 21, 20)]
xvals[2] <- xvals[2] + (10 * xvals[2] / 1e6)
xvals[3] <- xvals[3] - (10 * xvals[3] / 1e6)
xvals[6] <- xvals[6] + (12 * xvals[6] / 1e6)

## Perfect matches:
matchWithPpm(xvals, yvals)

## Match allowing +/- 10ppm difference
matchWithPpm(xvals, yvals, ppm = 10)

## Match allowing +/- 20ppm difference
matchWithPpm(xvals, yvals, ppm = 20)

michaelwitting/CompoundDb documentation built on April 29, 2020, 8:42 p.m.