Madhurig at 07:43, 21 October 2025

2025-10-21T07:43:32Z

Nirmala Venkat at 13:14, 13 October 2025

2025-10-13T13:14:30Z

Nirmala Venkat: Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || Welcome to the Spoken Tutorial on '''Iterators and Closures''' in''' Rust.''' |- style="border:1..."

2025-10-13T13:13:17Z

Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || Welcome to the Spoken Tutorial on '''Iterators and Closures''' in''' Rust.''' |- style="border:1..."

New page

{| border="1"
|-
|| '''Visual Cue'''
|| '''Narration'''
|-
|| '''Slide 1'''
|| Welcome to the Spoken Tutorial on '''Iterators and Closures''' in''' Rust.'''
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| '''Slide 2'''

'''Learning Objectives'''
|| In this tutorial, we will learn about:
* <div style="margin-left:1.27cm;margin-right:0cm;">Iterators </div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Types of Iterators</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Closures</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.101cm;padding-right:0.191cm;"
|| '''Slide 3'''

'''System Requirements'''
To record this tutorial I’m using

|| To record this tutorial I’m using the following setup.

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.101cm;padding-right:0.191cm;"
|| '''Slide''' '''5'''

'''Code Files'''
||
* <div style="margin-left:1.27cm;margin-right:0cm;">The following code file is required to practise this tutorial.</div>
* * <div style="margin-left:1.27cm;margin-right:0cm;">iterators.rs</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">This file is provided in the Code Files link of this tutorial page.</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.101cm;padding-right:0.191cm;"
|| '''Slide 6:'''

'''Iterators'''

|| Let us get started.
* <div style="margin-left:1.27cm;margin-right:0cm;">Iterators are powerful and flexible tools.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">They process sequences of data one at a time.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">They help to iterate over a collection of values such as arrays, vectors, maps, etc.</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.101cm;padding-right:0.191cm;"
|| '''Slide 7:'''

'''Type of Iterators'''

|| In Rust we can categorize iterators into 3 main types.
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Basic & Range Iterators '''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Iterator Adapters '''and</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Iterator Consumers/Collectors'''</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.101cm;padding-right:0.191cm;"
||
||

Let’s learn about '''Basic and Range Iterators''' with an example.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| Open '''Visual''' '''code editor'''
|| Open the '''Visual Studio code editor.'''
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| In the menu bar, click on '''Terminal''' and select''' New Terminal'''.

|| In the menu bar, click on '''Terminal''' and select''' New Terminal'''.

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| I have created the '''filehandling''' project as explained earlier.
|| Let us go to our working directory '''MyRustProject''' as explained earlier.

Type the command '''cargo new iterators '''and press '''Enter.'''

Open the created project as shown.

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| Point to the '''main.rs''' file.

|| <span style="background-color:#ffffff;">In the </span><span style="background-color:#ffffff;">'''main.rs '''</span><span style="background-color:#ffffff;">file, copy and paste the code from the Code file.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| fn main() {

let numbers = vec![1, 2, 3];

let mut iter = numbers.iter();

println!("{:?}", iter.next()); // Some(1)

println!("{:?}", iter.next()); // Some(2)

println!("{:?}", iter.next()); // Some(3)

println!("{:?}", iter.next()); // None

}
|| We declared a '''vector''' called '''numbers''' with values 1, 2, 3.

'''numbers.iter() method '''creates an iterator named '''iter.'''

'''iterator '''can safely access vector elements without looping.

'''next()''' method is used to traverse through the items.

It returns a value '''None''' when it reaches the end of the collection.

Save the program.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Run the code to see the output.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Let’s see an example of commonly used '''iterator adapters'''.

Clear the previous code.

Copy paste the code from the code file.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| fn main() {

let numbers = vec![1, 2, 3, 4, 5];

let squared: Vec<i32> = numbers

.iter()

.map(|x| x * x)

.collect();

println!("{:?}", squared); // [1, 4, 9, 16, 25]

}
|| We declare a vector of integers.

We then create an '''iterator''' using the '''.iter() '''method.

It gives us '''immutable references''' to each element in the vector.

'''.map() '''method uses a '''closure''' that takes each element x and returns <span style="color:#000000;">its </span><span style="color:#000000;">square</span>

This doesn't immediately compute the <span style="color:#000000;">square</span>.

It builds a new iterator pipeline that knows how to compute them when needed.

Finally, '''.collect() '''consumes the iterator and gathers the squares into a<span style="color:#ff0000;"> </span><span style="color:#000000;">new </span><span style="color:#000000;">vector</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Run the code to see the output.

The result is printed as a <span style="color:#000000;">new vector [1</span>, 4, 9, 16, 25]
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Let’s see an example of '''Iterator Consumers '''or''' Collectors.'''

These methods consume an iterator and return results like '''Vec, bool''', or a single value.

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Copy and paste the code from the code file.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| fn main() {

let numbers = vec![1, 2, 3, 4, 5, 6];

let evens: Vec<_> = numbers

.iter()

.filter(|x| *x % 2 == 0)

.collect();

println!("{:?}", evens); // [2, 4, 6]

}

|| This program shows how to use '''iterators '''with filters to show only even numbers from a vector.

Filter() method which takes a closure that returns true or false for each element.

The condition that we’ve used here will check if the number is even or not.

Only the elements that satisfy this condition are passed forward in the iterator pipeline.

Lastly, .collect() method gathers the remaining elements into new '''vector evens'''.

Save the program.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| In the terminal, type '''cargo run '''and see the output.

The result is [2, 4, 6], it contains only even numbers from the original list.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
||
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| '''Slide 6:'''

'''Closures'''
* <div style="margin-left:1.27cm;margin-right:0cm;">In Rust, closure is a function without names</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">It can capture variables from its environment, which is a key difference from regular functions.</div>

|| Next we will see about '''Closures'''.
* <div style="margin-left:1.27cm;margin-right:0cm;">Closure is a function without names</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">It can capture variables from its environment, which is a key difference from regular functions.</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Let us understand '''closures''' with an example.

Switch back to the visual code editor.

Clear the window and copy and paste the code from the codefile.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| fn main() {

// define a closure and store it in a variable

let add_one = |x: i32| x + 1;

// call closure and store the result in a variable

let result = add_one(2);

println!("Result = {}", result);

'''}'''
|| Here, parameters are placed between '''vertical <span style="color:#000000;">pipelines</span><span style="color:#ff0000;">.'''</span>

<span style="background-color:#ffffff;">We have defined a closure and binded it to the </span><span style="background-color:#ffffff;">'''add_one'''</span><span style="background-color:#ffffff;"> variable. </span>

<span style="background-color:#ffffff;">We then call the closure with </span><span style="background-color:#ffffff;">'''add_one(2)'''</span><span style="background-color:#ffffff;"> and bind the return value to the </span><span style="background-color:#ffffff;">'''result'''</span><span style="background-color:#ffffff;"> variable.</span>

'''Closures '''can omit''' type annotations '''and '''return types''', as Rust is capable of '''type inference'''

Save the program.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Run the code to see the output.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| <span style="color:#000000;">Let us see another example for multiple statements inside a closure.</span><span style="color:#ff0000;"> </span>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Clear the previous code. Copy paste the code from the code file.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| fn main() {

// define a multi-line closure

let squared_sum = |x: i32, y: i32| {

// find the sum of two parameters

let mut sum: i32 = x + y;

// find the squared value of the sum

let mut result: i32 = sum * sum;

return result;

};

// call the closure

let result = squared_sum(5, 3);

println!("Result = {}", result);

}
|| In this example, we enclose the multiple statements using curly braces {}.

First we calculate the sum of two parameters.

Then we find the squared value of the sum.

Save the program.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| In the terminal, type '''cargo run.'''

We can see the output as 64.

That is the sum of 5 and 3 is 8. The squared value is 64.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| This brings us to the end of this tutorial.

Let us summarize.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| Slide 8
* <div style="margin-left:1.27cm;margin-right:0cm;">Write a Rust program that takes a vector of integers:</div>

let numbers = vec![10, 15, 20, 25, 30, 35, 40];

* <div style="margin-left:1.27cm;margin-right:0cm;">Using iterators, perform the following steps:</div>

** <div style="margin-left:1.905cm;margin-right:0cm;">Filter out the numbers that are divisible by 10</div>
** <div style="margin-left:1.905cm;margin-right:0cm;">Collect the result into a new vector.</div>
** <div style="margin-left:1.905cm;margin-right:0cm;">Finally, print the resulting vector.</div>

|| As an assignment,
* <div style="margin-left:1.27cm;margin-right:0cm;">Write a Rust program that takes a vector of integers:</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Using iterators, perform the following steps:</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| '''Slide 9 Thank You'''
|| Thanks for joining.
|-
|}
<div style="margin-left:-1.588cm;margin-right:-1.429cm;"></div>

@@ Line 29: / Line 29: @@
 ||
 * <div style="margin-left:1.27cm;margin-right:0cm;">The following code file is required to practise this tutorial.</div>
-* * <div style="margin-left:1.27cm;margin-right:0cm;">iterators.rs</div>
+* <div style="margin-left:1.27cm;margin-right:0cm;">iterators.rs</div>
 * <div style="margin-left:1.27cm;margin-right:0cm;">This file is provided in the Code Files link of this tutorial page.</div>

Rust-Programming-Language/C2/Iterators-and-Closures/English - Revision history

Madhurig at 07:43, 21 October 2025

Nirmala Venkat at 13:14, 13 October 2025

Nirmala Venkat: Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || Welcome to the Spoken Tutorial on '''Iterators and Closures''' in''' Rust.''' |- style="border:1..."