[Rust] Variable : Python 코드 비교 예제 (58일차)

 

<예제 코드_1>

[Python]

if __name__ == '__main__':
    
    x = 1;
    print(x);
    # bind x again shadows old one from above
    x = 'i';
    print(x)

    # declare, init
    something = None;
    x = 5;
    print("x, something", x, something);
    something = x * 5;
    print("x, something", x, something);

    # mutability
    y = 0;
    y = y * 2 + x;
    print(y);

    BLAH = 42;  # only const by convention
    y *= BLAH;

 

[Rust]

fn main() {

    let x = 1;
    println!("x: {}", x);
    // binds x again, shadowning the old one from above
    let x = 'i';
    println!("x; {}", x);

    // declare, initialize
    let something;
    let x = 5;
    // println!("x, something: {}, {}", x, something); // Error
    something = x * 5;
    println!("x, something: {}, {}", x, something);

    // Mutablity
    let mut y = 0;  // Need to declare 'mut'
    y = y * 2 + x;
    dbg!(y);

    const BLAH: i32 = 42;   // need to change Upper Capital. Don't know why.
    y *= BLAH;
    dbg!(y);
}

 

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<예제 코드_2>

[Python]

# LEGB rule: Local, Enclosing, Global, and Built-in

global_variable = 1;

def f():
    global global_variable;
    local_variable = 2;
    def subf():
        print("local", local_variable);
        print("global", global_variable);
        enclosed_variable = 3;
        # local_variable = 5;
    
    subf();
    # print("enclosed", enclosed_variable);
    global_variable = 9;
    local_variable = 1;
    print("global", global_variable);
    print("local", local_variable);
    # example use of built-in scope
    blah = int("42");

if __name__ == '__main__':
    f();

 

[Rust]

fn main() {

    // scope
    // This binding lives in the main function
    let long_lived_binding = 1;

    // This is a block, and has a smaller scope than the main function
    {
        // This binding only exists in this block.
        let short_lived_binding = 2;

        println!("inner short: {}", short_lived_binding);

        // This binding "shadows" the outer one
        let long_lived_binding = 5_f32;

        println!("inner long: {}", long_lived_binding);
    }
    // End of the block

    // Error! `short_lived_binding` doesn't exist in this scope
    // println!("outer short: {}", short_lived_binding);

    println!("outer long: {}", long_lived_binding);

    // This binding also *shadows* the previous binding
    let long_lived_binding = 'a';

    println!("outer long: {}", long_lived_binding);
}

 

 

 

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<참조 1> https://www.youtube.com/watch?v=vlw0P8a40Oc

<참조_2>