Why does an `if statement` in R get evaluated without a logical condition?

Question

I noticed that if I pass any number except 0 as an argument to an if statement, the code inside the if statement compiles. I am confused why this is happening! I understand that R internally recognizes 0 as FALSE and the statement inside the if condition is not evaluated, which makes sense, but why is it getting evaluated for other numbers?

if(5) {
5 * 5
}

I had expected that I will get an error, but the code compiles and I get 25 as an answer.

Answer 1

From the ifhelp page, if expects:

A length-one logical vector ... Other types are coerced to logical if possible, ignoring any class

So basically it does

as.logical(5)
# [1] TRUE

既然是5 != 0，那就是真的

as.logical(0)
# [1] FALSE

在语言中很常见，任何非0的数字都被解释为“ true”