Copy
Copying is the creation of a separate representation of an existing value, object, or data, preserving some or all of its contents or state.
Python How-To
Object copying is the technique of creating a separate object representation from an existing object.
- How it is used
- Keeps an original task available while edits are made to a working copy that can be saved or discarded.
- How deep it goes
- Works through shallow copying, demonstrates shared mutable state, contrasts deep copying, and poses custom `__copy__` behavior as a challenge.
- Examples
- Uses editable tasks with tags, a shared-list identity check, and files copied into subject folders.
- What you can do after
- Apply it via Python’s `copy` module, choosing shallow or deep copying according to whether contained mutable objects must remain independent.
Get Programming: Learn to code with Python
Copying is the creation of a distinct object by transferring the elements or state of an original object.
- How it is used
- Creates separate mutable-object state when changes through shared aliases would cause unwanted side effects.
- How deep it goes
- Demonstrates list(), copy(), and sorted() with concrete results, and contrasts copies with aliases.
- Examples
- Uses artist lists, sorted ages, list filtering, and a stack method that returns copied elements.
- What you can do after
- Apply Python's list(), copy(), and sorted() to create separate or sorted lists without changing the original.
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Idiomatic Rust
The Rust Clone trait defines explicit duplication of a value through its clone method.
- How it is used
- Provides explicit duplication where a value is needed without relying on automatic Copy behavior.
- How deep it goes
- Defines Clone through its method, shows derivation and generic bounds, and cautions against overuse without detailing implementation internals.
- Examples
- Shows a derived Clone implementation on a struct, a clone() call, and a generic linked-list item bounded by Clone.
- What you can do after
- Apply it via Rust’s #[derive(Clone)] and clone(), while reconsidering duplication used merely to avoid borrowing.
The Quick Python Book, Fourth Edition
- How it is used
- Copies lists and dictionaries for further use while distinguishing shared nested contents from independent ones.
- How deep it goes
- Works through shallow and deep copy behavior with nested values, but does not cover copying internals.
- Examples
- Demonstrates nested-list mutations, list slicing, deepcopy, dictionary copy(), and tuple aliases.
- What you can do after
- Apply Python slicing, copy(), or copy.deepcopy() to choose the intended degree of independence.
Read how The Quick Python Book, Fourth Edition explains copy →
Code Like a Pro in Rust
Clone is a standard Rust trait that defines how a value can produce a duplicate of itself.
- How it is used
- Uses `Clone` to retain an independent owned value, then checks where string operations create avoidable duplicates.
- How deep it goes
- Demonstrates `clone()` and derived implementations, then gives signature-based copy heuristics; defers fuller trait treatment.
- Examples
- Uses a cloned vector modified after duplication, a struct deriving `Clone`, and string-lowercasing functions.
- What you can do after
- Apply Rust’s `clone()` and `#[derive(Clone)]` deliberately, and evaluate string APIs for unnecessary copies.
Related concepts
- Copy traitcontrasts with · Copy is a Rust marker trait indicating that values of a type can be duplicated implicitly rather than moved.
- deep copycontrasts with · A deep copy is an independent duplicate of a data structure that recursively copies its nested objects rather than sharing mutable contents with the original.
- viewcontrasts with · A view is an alternate representation or access interface for data derived from or backed by underlying storage without necessarily creating an independent copy.
- movecontrasts with · Move semantics describe the transfer of a value or its resources to another binding or object rather than duplicating them.
- traitkind of · A trait is a type-level construct that defines reusable behavior or members that types can implement or compose.
- shutilpart of · shutil is a Python standard-library module providing high-level operations for copying, moving, archiving, and managing files and directories.
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