Welcome to Software Development on Codidact!

Will you help us build our independent community of developers helping developers? We're small and trying to grow. We welcome questions about all aspects of software development, from design to code to QA and more. Got questions? Got answers? Got code you'd like someone to review? Please join us.

Post History

60%

+1 −0

Q&A How can I create and modify a struct over iterations of a loop?

You can use an Option to keep track of the mutable state between iterations. Use as_mut to get a mutable reference to the Option's inner value without consuming the Option. Use unwrap on the muta...

posted 3mo ago by Nisha Jadon‭ · edited 3mo ago by GeraldS‭

Answer

#3: Post edited by

GeraldS‭ · 2024-08-05T20:17:20Z (3 months ago)
code formatting

Copy Link

Raw

Markdown

**You can use an Option to keep track of the mutable state between iterations.**
**Use as_mut to get a mutable reference to the Option's inner value without consuming the Option.**
**Use unwrap on the mutable reference to access the inner value.**
_See this code just for reference_
~~`let mut sections: Vec<Section> = Vec::new();~~
let mut current_section: Option<Section> = None;
for line in read_to_string("input.ini").unwrap().lines() {
if line.trim().ends_with("]") {
if let Some(section) = current_section.take() {
sections.push(section);
}
current_section = Some(Section::new(line));
} else {
current_section.as_mut().unwrap().add_entry(line);
}
}
if let Some(section) = current_section {
sections.push(section);
}`

**You can use an Option to keep track of the mutable state between iterations.**
**Use as_mut to get a mutable reference to the Option's inner value without consuming the Option.**
**Use unwrap on the mutable reference to access the inner value.**
_See this code just for reference_
```rust
let mut sections: Vec<Section> = Vec::new();
let mut current_section: Option<Section> = None;
for line in read_to_string("input.ini").unwrap().lines() {
if line.trim().ends_with("]") {
if let Some(section) = current_section.take() {
sections.push(section);
}
current_section = Some(Section::new(line));
} else {
current_section.as_mut().unwrap().add_entry(line);
}
}
if let Some(section) = current_section {
sections.push(section);
}
```

#2: Post edited by

Nisha Jadon‭ · 2024-08-05T07:26:49Z (3 months ago)

Copy Link

Raw

Markdown

**You can use an Option to keep track of the mutable state between iterations.
~~Use as_mut to get a mutable reference to the Option's inner value without consuming the Option.~~
Use unwrap on the mutable reference to access the inner value.**
~~See this code just for reference,~~
~~_`let mut sections: Vec<Section> = Vec::new();~~
~~let mut current_section: Option<Section> = None;~~
~~for line in read_to_string("input.ini").unwrap().lines() {~~
if line.trim().ends_with("]") {
if let Some(section) = current_section.take() {
sections.push(section);
}
current_section = Some(Section::new(line));
} else {
current_section.as_mut().unwrap().add_entry(line);
}
}
~~if let Some(section) = current_section {~~
sections.push(section);
~~}`_~~

**You can use an Option to keep track of the mutable state between iterations.**
**Use as_mut to get a mutable reference to the Option's inner value without consuming the Option.**
**Use unwrap on the mutable reference to access the inner value.**
_See this code just for reference_
`let mut sections: Vec<Section> = Vec::new();
let mut current_section: Option<Section> = None;
for line in read_to_string("input.ini").unwrap().lines() {
if line.trim().ends_with("]") {
if let Some(section) = current_section.take() {
sections.push(section);
}
current_section = Some(Section::new(line));
} else {
current_section.as_mut().unwrap().add_entry(line);
}
}
if let Some(section) = current_section {
sections.push(section);
}`

#1: Initial revision by

Nisha Jadon‭ · 2024-08-05T07:24:37Z (3 months ago)

Copy Link

Raw

Markdown

**You can use an Option to keep track of the mutable state between iterations.

Use as_mut to get a mutable reference to the Option's inner value without consuming the Option.

Use unwrap on the mutable reference to access the inner value.**

See this code just for reference, 

_`let mut sections: Vec<Section> = Vec::new();
let mut current_section: Option<Section> = None;

for line in read_to_string("input.ini").unwrap().lines() {
    if line.trim().ends_with("]") {
        if let Some(section) = current_section.take() {
            sections.push(section);
        }
        current_section = Some(Section::new(line));
    } else {
        current_section.as_mut().unwrap().add_entry(line);
    }
}

if let Some(section) = current_section {
    sections.push(section);
}`_

Communities

Post History