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4 min readIn Rust, variables are immutable by default, which means they cannot be reassigned once they have been defined. However, if you want to use the same variable multiple times with different values, you can simply shadow the variable by redefining it.For example, if you have a variable named "num" with the value 10, and you want to use it with a different value later in your code, you can simply redefine the variable like this: fn main() { let num = 10; // original value println.
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6 min readIn Rust, you can't add new fields to a struct with a method. Once a struct is defined, its fields are fixed and cannot be altered. If you need to add new data to a struct, you'll have to define a new struct with the additional field and use it instead. Alternatively, you can use associated types or enums to define a more flexible data structure.
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7 min readTo export a function written in Rust to C code, you need to use the #[no_mangle] attribute in Rust. This attribute prevents the Rust compiler from "mangling" the function name, which means that the function name will be preserved as-is when compiled to C code. You also need to use the extern "C" block to specify that the function should be compiled as C code.
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4 min readTo send a vector to a spawned thread in Rust, you can utilize the Arc and Mutex types from the standard library. By wrapping the vector in an Arc, which stands for atomic reference counter, and a Mutex, you can safely share the vector between threads. When you spawn a new thread, you can pass a clone of the Arc into the thread closure, allowing the thread to access and modify the shared vector. Remember to use lock() method of Mutex to access the inner data of the vector in a thread-safe manner.
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4 min readTo make a hash map with a struct in Rust, you first need to define the struct that you want to store in the hash map. You can then create a HashMap instance by specifying the struct type as the key and value types.
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4 min readTo pass a struct method as a callback in Rust, you can use a combination of closures and trait objects.First, define a trait that represents the callback behavior, with a method that will be called when the callback is invoked. Then, implement the trait for the struct that contains the method you want to use as the callback.Next, create a closure that calls the method on the struct when it is invoked. This closure can then be passed as the callback function.
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4 min readIn Rust, it is not possible to directly modify variables outside of a nested scope without using mutable references. This is because Rust has strict rules around ownership and borrowing to prevent data races and ensure memory safety.If you want to modify a variable outside of a nested scope, you can use mutable references to the variable.
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4 min readTo remove everything from a substring in Rust, you can use the replace method from the String type. You can replace the substring with an empty string, effectively removing it from the original string. Alternatively, you can use the replace_range method to replace a range of characters with an empty string. Both methods will modify the original string in place.[rating:c1abfe4e-5b23-47e2-a608-65097a225475]How to scrub a string of unwanted characters in Rust.
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7 min readIn Rust, you can overwrite multiple lines of text by using the BufWriter module from the standard library. This module allows you to efficiently write data to a buffer and then overwrite it in a file.To overwrite multiple lines in Rust, you can first create a File object using the OpenOptions module. You can then wrap the File object in a BufWriter object to write data to the file.Using the write_all method from the Write trait, you can write the new lines of text to the buffer.
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6 min readIn Rust macros, you can use the ty and parse functions to parse a type. The ty function can be used to get the type of an expression, while the parse function can be used to parse a type from a string representation. To use these functions in a macro, you can define a new macro that takes an input, parses the type using parse, and then uses ty to get the type of the parsed value. This allows you to easily work with types in your Rust macros.
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4 min readTo test CLI arguments with Clap in Rust, you can use the App::get_matches_from or App::get_matches_from_safe methods provided by the Clap library.These methods allow you to pass in a vector of arguments to simulate the command line input. You can then access the parsed results and assert against them in your test code to verify that the expected arguments were parsed correctly.Additionally, you can use the assert_matches! macro provided by Clap to help with testing.