for循环

  1. let mut arr = vec![0;13];
  2. for value in arr.iter(){
  3.     //value += 1;  //value值不可修改
  4.     println!("value = {}", value);
  5. }
  1. let mut arr = vec![0;13];
  2. for value in arr.iter(){
  3.     value += 1; //value值可修改
  4.     println!("value = {}", value);
  5. }
  1.  let mut arr = vec![0;13];
  2.  for (index, value) in arr.iter().enumerate(){ //index是下标，value是值
  3.      println!("index = {}, value = {}", index, value);
  4.  }
  5. for (index, value) in arr.iter_mut().enumerate(){  //可修改值的循环器
  6.     *value = 1;
  7.     println!("index = {}, value = {}", index, value);
  8.  }
  1. let mut arr = vec![0;13];
  2. for i in 0..arr.len(){
  3.     println!("arr value = {}", arr[i]);
  4. }
  1. let mut arr = vec![0;13];
  2. for (index,value) in arr.iter().take(5).enumerate(){
  3.     println!("index = {}, value = {}", index, value);
  4. }