CODEWITHSUNDEEP
rlapply
Heisenberg
Heisenberg

Reputation: 8806

lapply with different optional argument for each element

The following lapply multiply each element in the list by 2

lapply(1:5, function(x, y) x * y, y = 2)

Is it possible to use lapply to specify a different y for each element in the list? The following pseudo code is an example:

lapply(1:5, function(x, y) x * y, y = 1 if x is odd and = 2 if x is even)

Upvotes: 1

Views: 120

Answers (1)

MrFlick
MrFlick

Reputation: 206242

sapply and lapply only allow for one varying argument. If you have multiple you can use mapply or Map. For example

x<-1:5
mapply(function(x, y) x * y, x, 2-(x %% 2))
# [1] 1 4 3 8 5

Here we use 2-(1:5 %% 2) to get a 1 for odds and 2 for evens.

Upvotes: 2

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