Can I conditionally provide an initialization for a vector or no initialization at all?
fn main() {
let b = true;
let a = vec![
if b {"b"} //error[E0317]: `if` may be missing an `else` clause
];
println!("{:?}", a);
}
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2 Answers
The vec! macro doesn't support this, but you can use normal functions on Vec:
fn main() {
let b = true;
let mut a = Vec::new();
if b {
a.push("b");
}
println!("{:?}", a);
}
2 Comments
Masklinn
Alternatively, just have to different vecs:
if b { vec!["b"] } else { vec![] }
Ömer Erden
If you want to protect immutability in a better way @Masklinn's alternative solution can be much more accurate.
You can do this:
let my_vec = if condition {
vec!["b"]
}
else{
vec![]
};
Another option is late initialization:
let my_vec: Vec<&str>;
if condition{
my_vec = vec![];
}
else{
my_vec = vec!["b"];
}
