I'm converting some Ruby/Crystal code to Rust and having problem with string<>number conversions. Here's is snippet with problem. The Ruby version looks like this: left_half = front_half.to_s (palindrome = (left_half + left_half.reverse).to_i; basep = base11) if power.odd? (palind…

Regarding the error message: parse returns a Result since it can fail on invalid input. Since you know the input is valid you can safely unwrap the result so you’re adding u64 + u64 and not trying to add u64 + Result<u64, ...>.

So what should the code look like?

Sorry, but I’m on mobile and have a hard time running the code but it should look something like: palindrome = (this_lo * 10) + left_half.chars().rev().collect::<String>().parse::<u64>().unwrap()

Thank you that worked, so that problem solved. :slightly_smiling_face: Is there a simple way to do equivalent in Ruby|Crystal: left_half.[r|chop] Just an observation: I spent about 6 hours searching online (stackoverflow, forum, docs, etc) last night to answer this question, and got so fed up and…

[image] jzakiya: I couldn't find a simple way to do the equivalent of chop|rchop to remove the last char of a string; // `pop()` returns an `Option<char>` in case you have an empty string (no last character) last_char = string_value.pop().unwrap(); // string_value is now one character shorter…

I feel your pain. I suffered as you do when I first started using Rust. The problem is that I have been trained to ignore compiler error messages. In most languages the error messages seem to be designed to confuse. That's not the case with Rust. In your example, the error message is telling yo…

Thank's for the empathy. I actually had started with getting 20+ error messages, and whittled it down to that last issue. Maybe if it wasn't so late, or I wasn't so tired, or so just fed up, I would have figured it out by myself. Rust is good at what it's designed for, and worth learning, but damn…

If it’s any comfort, Rust is the first programming language that I had to learn from first principles in a very long time. Returning Result, and learning how to read all the type information in general, is one of those things that takes a little time but then becomes immensely useful once you do. L…

OK, I hit another wall. for front_half in (this_lo..next_lo-1).step_by(10) { // d_00; d_10; d_20; ... let (mut palindrome, mut left_half) = (0u64, front_half.to_string()); if power & 1 == 1 { basep = base11; palindrome = left_half.push_str(&left_half.chars().rev().collect::<String>()…

String push returns (), not the result string as you can see from the source code. pub fn push(&mut self, ch: char) { // Some stuff }

Number -> string back to string.reverse -> number

help

quinedot November 26, 2020, 12:27am 15

I'm somewhat curious what the intended program and/or end result are, if you have any interest in sharing.

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Number -> string back to string.reverse -> number

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