How to iterate and extract values out of a for loop in Rust - for-loop

Question

I'm new to Rust and looking to understand concepts like borrowing. I'm trying to create a simple two dimensional array using standard input. The code:
use std::io;
fn main() {
let mut values = [["0"; 6]; 6]; // 6 * 6 array
// iterate 6 times for user input
for i in 0..6 {
let mut outputs = String::new();
io::stdin().read_line(&mut outputs).expect(
"failed to read line",
);
// read space separated list 6 numbers. Eg: 5 7 8 4 3 9
let values_itr = outputs.trim().split(' ');
let mut j = 0;
for (_, value) in values_itr.enumerate() {
values[i][j] = value;
j += 1;
}
}
}
This won't compile because the outputs variable lifetime is not long enough:
error[E0597]: `outputs` does not live long enough
--> src/main.rs:20:5
|
14 | let values_itr = outputs.trim().split(' ');
| ------- borrow occurs here
...
20 | }
| ^ `outputs` dropped here while still borrowed
21 | }
| - borrowed value needs to live until here
How can I get the iterated values out of the block into values array?

Answer 1

split() gives you substrings (string slices) borrowed from the original string, and the original string is outputs from line 6.
The string slices can't outlive the scope of outputs: when a loop iteration ends, outputs is deallocated.
Since values is longer lived, the slices can't be stored there.
We can't borrow slices of outputs across a modification of outputs. So even if the String outputs itself was defined before values, we couldn't easily put the string slices from .split() into values; modifying the string (reading into it) invalidates the slices.
A solution needs to either
Use a nested array of String, and when you assign an element from the split iterator, make a String from the &str using .to_string(). I would recommend this solution. (However an array of String is not at as easy to work with, maybe already this requires using Vec instead.) 1
Read all input before constructing a nested array of &str that borrows from the input String. This is good if the nested array is something that you only need temporarily.
1: You can use something like vec![vec![String::new(); 6]; 6] instead

Answer 2

This answer was moved from the question, where it solved the OPs needs.
use std::io;
fn main() {
let mut values = vec![vec![String::new(); 6]; 6];
for i in 0..6 {
let mut outputs = String::new();
io::stdin().read_line(&mut outputs)
.expect("failed to read line");
let values_itr = outputs.trim().split(' ');
let mut j = 0;
for (_, value) in values_itr.enumerate() {
values[i][j] = value.to_string();
j += 1;
}
}
}