user1181337 - 6 months ago 53

R Question

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,"`

Answer

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)
```