Iliana  Welch

Iliana Welch

1590896940

Rust Functions and Procedures

This Rust programming language tutorial series is aimed at easing your training step by step. Rust is a systems level language aimed at speed and safety and can be run cross-platform, including embedded systems and even the browser with WebAssembly (WASM)! I use the VS Code development environment to help you learn the core topics. Please join me on this journey with this fantastic new programming language.

Subscribe to the channel https://www.youtube.com/watch?v=hEhnDRR4Ijs

#functions #rust #procedures

What is GEEK

Buddha Community

Rust Functions and Procedures
Iliana  Welch

Iliana Welch

1590896940

Rust Functions and Procedures

This Rust programming language tutorial series is aimed at easing your training step by step. Rust is a systems level language aimed at speed and safety and can be run cross-platform, including embedded systems and even the browser with WebAssembly (WASM)! I use the VS Code development environment to help you learn the core topics. Please join me on this journey with this fantastic new programming language.

Subscribe to the channel https://www.youtube.com/watch?v=hEhnDRR4Ijs

#functions #rust #procedures

Vincent Lab

Vincent Lab

1605017502

The Difference Between Regular Functions and Arrow Functions in JavaScript

Other then the syntactical differences. The main difference is the way the this keyword behaves? In an arrow function, the this keyword remains the same throughout the life-cycle of the function and is always bound to the value of this in the closest non-arrow parent function. Arrow functions can never be constructor functions so they can never be invoked with the new keyword. And they can never have duplicate named parameters like a regular function not using strict mode.

Here are a few code examples to show you some of the differences
this.name = "Bob";

const person = {
name: “Jon”,

<span style="color: #008000">// Regular function</span>
func1: <span style="color: #0000ff">function</span> () {
    console.log(<span style="color: #0000ff">this</span>);
},

<span style="color: #008000">// Arrow function</span>
func2: () =&gt; {
    console.log(<span style="color: #0000ff">this</span>);
}

}

person.func1(); // Call the Regular function
// Output: {name:“Jon”, func1:[Function: func1], func2:[Function: func2]}

person.func2(); // Call the Arrow function
// Output: {name:“Bob”}

The new keyword with an arrow function
const person = (name) => console.log("Your name is " + name);
const bob = new person("Bob");
// Uncaught TypeError: person is not a constructor

If you want to see a visual presentation on the differences, then you can see the video below:

#arrow functions #javascript #regular functions #arrow functions vs normal functions #difference between functions and arrow functions

Rust Lang Course For Beginner In 2021: Guessing Game

 What we learn in this chapter:
- Rust number types and their default
- First exposure to #Rust modules and the std::io module to read input from the terminal
- Rust Variable Shadowing
- Rust Loop keyword
- Rust if/else
- First exposure to #Rust match keyword

=== Content:
00:00 - Intro & Setup
02:11 - The Plan
03:04 - Variable Secret
04:03 - Number Types
05:45 - Mutability recap
06:22 - Ask the user
07:45 - First intro to module std::io
08:29 - Rust naming conventions
09:22 - Read user input io:stdin().read_line(&mut guess)
12:46 - Break & Understand
14:20 - Parse string to number
17:10 - Variable Shadowing
18:46 - If / Else - You Win, You Loose
19:28 - Loop
20:38 - Match
23:19 - Random with rand
26:35 - Run it all
27:09 - Conclusion and next episode

#rust 

Rust  Language

Rust Language

1575568089

The Rust Programming Language - Understanding Functions in Rust

Every Rust program has at least one function, the main function:

fn main() {
}

This is the simplest possible function declaration. As we mentioned before, fn says ‘this is a function’, followed by the name, some parentheses because this function takes no arguments, and then some curly braces to indicate the body. Here’s a function named foo:


# #![allow(unused_variables)]
#fn main() {
fn foo() {
}
#}

So, what about taking arguments? Here’s a function that prints a number:


# #![allow(unused_variables)]
#fn main() {
fn print_number(x: i32) {
    println!("x is: {}", x);
}
#}

Here’s a complete program that uses print_number:

fn main() {
    print_number(5);
}

fn print_number(x: i32) {
    println!("x is: {}", x);
}

As you can see, function arguments work very similar to let declarations: you add a type to the argument name, after a colon.

Here’s a complete program that adds two numbers together and prints them:

fn main() {
    print_sum(5, 6);
}

fn print_sum(x: i32, y: i32) {
    println!("sum is: {}", x + y);
}

You separate arguments with a comma, both when you call the function, as well as when you declare it.

Unlike let, you must declare the types of function arguments. This does not work:

fn print_sum(x, y) {
    println!("sum is: {}", x + y);
}

You get this error:

expected one of `!`, `:`, or `@`, found `)`
fn print_sum(x, y) {

This is a deliberate design decision. While full-program inference is possible, languages which have it, like Haskell, often suggest that documenting your types explicitly is a best-practice. We agree that forcing functions to declare types while allowing for inference inside of function bodies is a wonderful sweet spot between full inference and no inference.

What about returning a value? Here’s a function that adds one to an integer:


# #![allow(unused_variables)]
#fn main() {
fn add_one(x: i32) -> i32 {
    x + 1
}
#}

Rust functions return exactly one value, and you declare the type after an ‘arrow’, which is a dash (-) followed by a greater-than sign (>). The last line of a function determines what it returns. You’ll note the lack of a semicolon here. If we added it in:

fn add_one(x: i32) -> i32 {
    x + 1;
}

We would get an error:

error: not all control paths return a value
fn add_one(x: i32) -> i32 {
     x + 1;
}

help: consider removing this semicolon:
     x + 1;
          ^

This reveals two interesting things about Rust: it is an expression-based language, and semicolons are different from semicolons in other ‘curly brace and semicolon’-based languages. These two things are related.

Expressions vs. Statements

Rust is primarily an expression-based language. There are only two kinds of statements, and everything else is an expression.

So what’s the difference? Expressions return a value, and statements do not. That’s why we end up with ‘not all control paths return a value’ here: the statement x + 1; doesn’t return a value. There are two kinds of statements in Rust: ‘declaration statements’ and ‘expression statements’. Everything else is an expression. Let’s talk about declaration statements first.

In some languages, variable bindings can be written as expressions, not statements. Like Ruby:

x = y = 5

In Rust, however, using let to introduce a binding is not an expression. The following will produce a compile-time error:

let x = (let y = 5); // Expected identifier, found keyword `let`.

The compiler is telling us here that it was expecting to see the beginning of an expression, and a let can only begin a statement, not an expression.

Note that assigning to an already-bound variable (e.g. y = 5) is still an expression, although its value is not particularly useful. Unlike other languages where an assignment evaluates to the assigned value (e.g. 5 in the previous example), in Rust the value of an assignment is an empty tuple () because the assigned value can have only one owner, and any other returned value would be too surprising:


# #![allow(unused_variables)]
#fn main() {
let mut y = 5;

let x = (y = 6);  // `x` has the value `()`, not `6`.
#}

The second kind of statement in Rust is the expression statement. Its purpose is to turn any expression into a statement. In practical terms, Rust’s grammar expects statements to follow other statements. This means that you use semicolons to separate expressions from each other. This means that Rust looks a lot like most other languages that require you to use semicolons at the end of every line, and you will see semicolons at the end of almost every line of Rust code you see.

What is this exception that makes us say “almost”? You saw it already, in this code:


# #![allow(unused_variables)]
#fn main() {
fn add_one(x: i32) -> i32 {
    x + 1
}
#}

Our function claims to return an i32, but with a semicolon, it would return () instead. Rust realizes this probably isn’t what we want, and suggests removing the semicolon in the error we saw before.

Early returns

But what about early returns? Rust does have a keyword for that, return:


# #![allow(unused_variables)]
#fn main() {
fn foo(x: i32) -> i32 {
    return x;

    // We never run this code!
    x + 1
}
#}

Using a return as the last line of a function works, but is considered poor style:


# #![allow(unused_variables)]
#fn main() {
fn foo(x: i32) -> i32 {
    return x + 1;
}
#}

The previous definition without return may look a bit strange if you haven’t worked in an expression-based language before, but it becomes intuitive over time.

Diverging functions

Rust has some special syntax for ‘diverging functions’, which are functions that do not return:


# #![allow(unused_variables)]
#fn main() {
fn diverges() -> ! {
    panic!("This function never returns!");
}
#}

panic! is a macro, similar to println!() that we’ve already seen. Unlike println!(), panic!() causes the current thread of execution to crash with the given message. Because this function will cause a crash, it will never return, and so it has the type ‘!’, which is read ‘diverges’.

If you add a main function that calls diverges() and run it, you’ll get some output that looks like this:

thread ‘main’ panicked at ‘This function never returns!’, hello.rs:2

If you want more information, you can get a backtrace by setting the RUST_BACKTRACE environment variable:

$ RUST_BACKTRACE=1 ./diverges
thread 'main' panicked at 'This function never returns!', hello.rs:2
Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
  hello::diverges
        at ./hello.rs:2
  hello::main
        at ./hello.rs:6

If you want the complete backtrace and filenames:

$ RUST_BACKTRACE=full ./diverges
thread 'main' panicked at 'This function never returns!', hello.rs:2
stack backtrace:
   1:     0x7f402773a829 - sys::backtrace::write::h0942de78b6c02817K8r
   2:     0x7f402773d7fc - panicking::on_panic::h3f23f9d0b5f4c91bu9w
   3:     0x7f402773960e - rt::unwind::begin_unwind_inner::h2844b8c5e81e79558Bw
   4:     0x7f4027738893 - rt::unwind::begin_unwind::h4375279447423903650
   5:     0x7f4027738809 - diverges::h2266b4c4b850236beaa
   6:     0x7f40277389e5 - main::h19bb1149c2f00ecfBaa
   7:     0x7f402773f514 - rt::unwind::try::try_fn::h13186883479104382231
   8:     0x7f402773d1d8 - __rust_try
   9:     0x7f402773f201 - rt::lang_start::ha172a3ce74bb453aK5w
  10:     0x7f4027738a19 - main
  11:     0x7f402694ab44 - __libc_start_main
  12:     0x7f40277386c8 - <unknown>
  13:                0x0 - <unknown>

If you need to override an already set RUST_BACKTRACE, in cases when you cannot just unset the variable, then set it to 0 to avoid getting a backtrace. Any other value (even no value at all) turns on backtrace.

$ export RUST_BACKTRACE=1
...
$ RUST_BACKTRACE=0 ./diverges 
thread 'main' panicked at 'This function never returns!', hello.rs:2
note: Run with `RUST_BACKTRACE=1` for a backtrace.

RUST_BACKTRACE also works with Cargo’s run command:

$ RUST_BACKTRACE=full cargo run
     Running `target/debug/diverges`
thread 'main' panicked at 'This function never returns!', hello.rs:2
stack backtrace:
   1:     0x7f402773a829 - sys::backtrace::write::h0942de78b6c02817K8r
   2:     0x7f402773d7fc - panicking::on_panic::h3f23f9d0b5f4c91bu9w
   3:     0x7f402773960e - rt::unwind::begin_unwind_inner::h2844b8c5e81e79558Bw
   4:     0x7f4027738893 - rt::unwind::begin_unwind::h4375279447423903650
   5:     0x7f4027738809 - diverges::h2266b4c4b850236beaa
   6:     0x7f40277389e5 - main::h19bb1149c2f00ecfBaa
   7:     0x7f402773f514 - rt::unwind::try::try_fn::h13186883479104382231
   8:     0x7f402773d1d8 - __rust_try
   9:     0x7f402773f201 - rt::lang_start::ha172a3ce74bb453aK5w
  10:     0x7f4027738a19 - main
  11:     0x7f402694ab44 - __libc_start_main
  12:     0x7f40277386c8 - <unknown>
  13:                0x0 - <unknown>

A diverging function can be used as any type:


# #![allow(unused_variables)]
#fn main() {
# fn diverges() -> ! {
#    panic!("This function never returns!");
# }
let x: i32 = diverges();
let x: String = diverges();
#}

Function pointers

We can also create variable bindings which point to functions:


# #![allow(unused_variables)]
#fn main() {
let f: fn(i32) -> i32;
#}

f is a variable binding which points to a function that takes an i32 as an argument and returns an i32. For example:


# #![allow(unused_variables)]
#fn main() {
fn plus_one(i: i32) -> i32 {
    i + 1
}

// Without type inference:
let f: fn(i32) -> i32 = plus_one;

// With type inference:
let f = plus_one;
#}

We can then use f to call the function:


# #![allow(unused_variables)]
#fn main() {
# fn plus_one(i: i32) -> i32 { i + 1 }
# let f = plus_one;
let six = f(5);
#}

#Functions #Rust #WebDev

Tia  Gottlieb

Tia Gottlieb

1598258520

Activation Functions, Optimization Techniques, and Loss Functions

Activation Functions:

A significant piece of a neural system Activation function is numerical conditions that decide the yield of a neural system. The capacity is joined to every neuron in the system and decides if it ought to be initiated (“fired”) or not, founded on whether every neuron’s info is applicable for the model’s expectation. Initiation works likewise help standardize the yield of every neuron to a range somewhere in the range of 1 and 0 or between — 1 and 1.

Progressively, neural systems use linear and non-linear activation functions, which can enable the system to learn complex information, figure and adapt practically any capacity speaking to an inquiry, and give precise forecasts.

Linear Activation Functions:

**Step-Up: **Activation functions are dynamic units of neural systems. They figure the net yield of a neural node. In this, Heaviside step work is one of the most widely recognized initiation work in neural systems. The capacity produces paired yield. That is the motivation behind why it is additionally called paired advanced capacity.

The capacity produces 1 (or valid) when info passes edge limit though it produces 0 (or bogus) when information doesn’t pass edge. That is the reason, they are extremely valuable for paired order studies. Every rationale capacity can be actualized by neural systems. In this way, step work is usually utilized in crude neural systems without concealed layer or generally referred to name as single-layer perceptions.

#machine-learning #activation-functions #loss-function #optimization-algorithms #towards-data-science #function