Lazyifelse: Lazy version of ifelse

In EmilBode/EmilMisc: Miscellaneous Functions I Found Useful

Description

When using ifelse, the return values are evaluated for all values, then discarded. This causes problems when you want to check for valid inputs in test. In this function, values are only evaluated when necessary: yFun is called with yIn for test==TRUE, and nFun is called with nIn for test==FALSE. Missing (NA) values in test return NA, without calling either yFun or nFun

Usage

Lazyifelse(test, yFun, yIn, nFun, nIn)

Arguments

test	an object which can be coerced to logical
yFun, nFun	Functions to be called when test evaluates to TRUE or FALSE respectively
yIn, nIn	Arguments for yFun and nFun. Recycled if necessary

Details

If you just want to return values, you can use the function identity

Examples

stats <- list(a=NA,
              b=list(time="1:00", speed=100))
besttimes <- Lazyifelse(is.na(stats), identity, NA, function(x) {sapply(x, `[[`, i='time')}, stats)

EmilBode/EmilMisc documentation built on Feb. 24, 2020, 4:11 p.m.