Merge branch 'mr/492-create-lab-for-module-iterators-2' into 'master'

Resolve "Create Lab for Module: Iterators"

Closes #492

See merge request feng/training/material!586

Author: Dana Binkley

courses/rust_essentials/170_iterators/88-iterators.lab.rst

@@ -2,8 +2,17 @@
 Lab
 =====
 
------
-TBD
------
+------------------
+Lab Instructions
+------------------
 
-TBD
+- Solve for compilation errors
+
+- Follow the hints!
+
+- Success is
+
+    - Code that compiles
+
+    - ...and that follows any behavior indicated within the hints!
+	

courses/rust_essentials/170_iterators/lab/answer/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "lab"
+name = "answer"
 version = "1.0.0"
 edition = "2024"
 

courses/rust_essentials/170_iterators/lab/answer/src/main.rs

@@ -1,3 +1,113 @@
+//! Lab (answer)
+//! Iterators
+//!
+//! Fix all the compile errors below and/or follow the hints provided
+//!
+
 fn main() {
-    println!("TBD");
+    // TASK 1 - Looping via Array Indices
+    // Hint: Print ALL values. Check the output to verify you printed all elements  
+    let array = [2, 4, 6, 8];
+    for idx in 0..4 {
+        println!("{}", array[idx]);
+    }
+    
+    // TASK 2 - Using Our Iterator
+    // Hint: The 'for' loop calls '.next()' under the hood
+    struct SliceIter<'s> {
+        slice: &'s [i32],
+        idx: usize,
+    }
+    impl<'s> Iterator for SliceIter<'s> {
+        type Item = &'s i32;
+        fn next(&mut self) -> Option<Self::Item> {
+            if self.idx == self.slice.len() {
+                None
+            } else {
+                let next = &self.slice[self.idx];
+                self.idx += 1;
+                Some(next)
+            }
+        }
+    }
+    let numbers = [10, 20, 30];
+    let iter = SliceIter {
+        slice: &numbers,
+        idx: 0,
+    };
+    for my_iter in iter {
+        println!("The number is: {}", my_iter);
+    }
+
+    // TASK 3 - Getting an Iterator - 'iter()'
+    // Hint: Collections themselves are not iterators
+    // Using 'iter()' does not consume the collection
+    let numbers_2 = vec![10, 20, 30];
+    for n in numbers_2.iter() {
+        println!("{n}");
+    }
+    println!("Done printing {} items.", numbers_2.len());    
+
+    // TASK 4 - Common Iterator Adapters
+    // Hint: 'map' transforms values during iteration, 'filter' selects values matching condition
+    fn double(x: &i32) -> i32 {
+        x * 2
+    }
+    fn is_even(x: &&i32) -> bool {
+        **x % 2 == 0
+    }
+    let flush = vec![10, 11, 12, 13, 14];
+
+    // Multiply all values by 2
+    for elem in flush.iter().map(double) {
+        println!("Value multiplied by 2 is: {elem}");
+    }
+    // Print only values divisible by 2
+    for elem in flush.iter().filter(is_even) {
+        println!("This value is divisible by 2: {elem}");
+    }
+    
+    // TASK 5 - Common Consumers
+    // Hint: 'sum' adds all values and return a single value, 'any' returns True if any value matches condition
+    fn is_freezing(temp: &i32) -> bool {
+        *temp < 0
+    }
+    let hand = [1, 2, 3, 4, 5];
+    // Sum all values into 'Total'
+    let total: i32 = hand.iter().sum();
+    println!("The total is: {total}");
+    
+    let temperatures = [22, 28, -2, 15, 30];
+    // Print the warning if any temperature is below 0
+    if temperatures.iter().any(is_freezing){
+        println!("Warning: Freezing temperatures detected!");
+    } else {
+        println!("All temperatures are above freezing.");
+    }
+    
+    // TASK 6 - Chaining
+    // Hint: Chaining allows you to create a new set of data before consuming
+    fn is_even_owned(x: &i32) -> bool {
+        *x % 2 == 0
+    }
+    fn square (x: i32) -> i32 {
+        x * x
+    }
+    let result: i32 = (1..=10) // Range: 1, 2, 3, ..., 10
+        .filter(is_even_owned) // Only select even values
+        .map(square)           // Square values
+        .sum();                // Total: 220
+    println!("Sum of even squares: {}", result);
+        
+    // TASK 7 - Collecting "Result"
+    // Hint: 'collect()' stores results in a collection
+    fn parse_i32(s: &str) -> Result<i32, std::num::ParseIntError> {
+        s.parse::<i32>()
+    }
+    let good_strings = vec!["1", "2", "42"];
+    let good_numbers: Result<Vec<i32>, _> = good_strings
+        .into_iter()
+        .map(parse_i32)
+        .collect();
+    println!("good_numbers: {:?}", good_numbers);
 }

courses/rust_essentials/170_iterators/lab/prompt/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "lab"
+name = "prompt"
 version = "1.0.0"
 edition = "2024"
 

courses/rust_essentials/170_iterators/lab/prompt/src/main.rs

@@ -1,3 +1,109 @@
+//! Lab (prompt)
+//! Iterators
+//!
+//! Fix all the compile errors below and/or follow the hints provided
+//!
+
 fn main() {
-    println!("TBD");
+    // TASK 1 - Looping via Array Indices
+    // Hint: Print ALL values. Check the output to verify you printed all elements  
+    let array = [2, 4, 6, 8];
+    for idx in 1..4 {
+        println!("{}", X);
+    }
+    
+    // TASK 2 - Using Our Iterator
+    // Hint: The 'for' loop calls .next() under the hood
+    struct SliceIter<'s> {
+        slice: &'s [i32],
+        idx: usize,
+    }
+    impl<'s> Iterator for SliceIter<'s> {
+        type Item = &'s i32;
+        fn next(&mut self) -> Option<Self::Item> {
+            if self.idx == self.slice.len() {
+                None
+            } else {
+                let next = &self.slice[self.idx];
+                self.idx += 1;
+                Some(next)
+            }
+        }
+    }
+    let numbers = [10, 20, 30];
+    let iter = SliceIter {
+        slice: &numbers,
+        idx: 0,
+    };
+    for X in Y {
+        println!("The number is: {}", X);
+    }
+
+    // TASK 3 - Getting an Iterator - 'iter()'
+    // Hint: Collections themselves are not iterators
+    let numbers_2 = vec![10, 20, 30];
+    for n in numbers_2 {
+        println!("{n}");
+    }
+    println!("Done printing {} items.", numbers_2.len());      
+    
+    // TASK 4 - Common Iterator Adapters
+    // Hint: 'map' transforms values during iteration, 'filter' selects values matching condition
+    fn double(x: &i32) -> i32 {
+        x * 2
+    }
+    fn is_even(x: &&i32) -> bool {
+        **x % 2 == 0
+    }
+    let flush = vec![10, 11, 12, 13, 14];
+    // Multiply all values by 2
+    for elem in flush.iter {
+        println!("Value multiplied by 2 is: {elem}");
+    }
+    // Print only values divisible by 2
+    for elem in flush.iter {
+        println!("this value is divisible by 2: {elem}");
+    }
+    
+    // TASK 5 - Common consumers
+    // Hint: 'sum' adds all values and return a single value, 'any' returns True if any value matches condition
+    fn is_freezing(temp: &i32) -> bool {
+        *temp < 0
+    }
+    let hand = [1, 2, 3, 4, 5];
+    // Sum all values into 'Total'
+    let total: i32 = hand.iter;
+    println!("The total is: {total}");
+    let temperatures = [22, 28, -2, 15, 30];
+    // Print the warning if any temperature is below 0
+    if temperatures.iter{
+        println!("Warning: Freezing temperatures detected!");
+    } else {
+        println!("All temperatures are above freezing.");
+    }
+    
+    // TASK 6 - Chaining
+    // Hint: Chaining allows you to create a new set of data before consuming
+    fn is_even_owned(x: &i32) -> bool {
+        *x % 2 == 0
+    }
+    fn square (x: i32) -> i32 {
+        x * x
+    }
+    let result: i32 = (1..=10) // Range: 1, 2, 3, ..., 10
+        .X                     // Only select even values
+        .Y                     // Square values
+        .sum();                // Total: 220
+    println!("Sum of even squares: {}", result);
+
+    // TASK 7 - Collecting "Result"
+    // Hint: 'collect()' stores results in a collection
+    fn parse_i32(s: &str) -> Result<i32, std::num::ParseIntError> {
+        s.parse::<i32>()
+    }
+    let good_strings = vec!["1", "2", "42"];
+    let good_numbers: Result<Vec<i32>, _> = good_strings
+        .into_iter()
+        .map(parse_i32)
+    println!("good_numbers: {:?}", good_numbers);    
 }