CODEWITHSUNDEEP
rif-statementlapply
rsgmon
rsgmon

Reputation: 1932

Using lapply with if to test each element in a list

Suppose I have a list:

alist<- list(4,6,8,9)

I want test if each list element is greater than 7 and return a list of 1 if its true and 0 if false.

However I must use lapply.

lapply(alist,if,>7,1) or lapply(alist,if,cond>7,1)

Of course none of these work and I keep getting the following error.

Error: unexpected ',' in "lapply(alist, if,"

Upvotes: 9

Views: 23111

Answers (2)

DRozen
DRozen

Reputation: 427

Another two:

lapply(alist > 7, as.integer)

or

lapply(alist > 7, ifelse, 1, 0)

Upvotes: 3

Tyler Rinker
Tyler Rinker

Reputation: 110034

It pains me to answer this because it's very un R to do this. You could try being more explicit and use brackets as in:

lapply(alist, function(x) if (x > 7) {1} else {0})

Or the vectorized ifelse 

lapply(alist, function(x) ifelse(x > 7, 1, 0))

Or best of all:

as.numeric(alist > 7)

Upvotes: 25

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