9.vectors.md

Vectors

• Vectors are resizable arrays

• Two ways to create a vector:

  • vec! macro

    let my_vec: Vec<i32> = vec![1, 2, 3, 4, 5];

  • Vec::new();

    let mut my_vec = Vec::new();

• Access an Element of a Vector my_vec[0]

• Print the Vector

  fn main() {   
      let my_vec = vec![1, 2, 3,4,5];
      //using debug trait 
      println!("Vector : {:?}", my_vec);
      println!("Print using for loop"); 
      // using loop
      let mut index = 0;
      for i in my_vec {
          println!("Element at index {}:{} ", index, i);
          index = index+1;
      }
  }

• Methods of Vectors

  • Vec::new()
  • push(arg)
  • pop()
  • contains(arg)
  • remove(index)
  • len()
  • reserve()
  • capacity()
  • and more

• Iterating on values in vector

  • iter() method

    let my_vec = vec![1, 2, 3, 4, 5];
    // using loop
    let mut index = 0;
    for i in my_vec.iter(){ // it works even if .iter() is not written
        println!("Element at index {}:{} ", index, i);
        index = index + 1;
    }   

• Iterate and Mutate Values

  • .iter_mut() method

    let mut my_vec = vec![1, 2, 3, 4, 5];
    println!("Initial Vector : {:?}", my_vec);
    for x in my_vec.iter_mut(){
       *x *= 3;
    }
    // print the updated vector
    println!("Updated Vector : {:?}", my_vec); 

• slicing a vector

      let my_vec = vec![1, 2, 3, 4, 5];
      let slice:&[i32] = &my_vec[2..4];
      // print the vector
      println!("Slice of the vector : {:?}",slice);

• vector can be of type enum