5 ms·

> python is very expressive, hence the code base have way less numbers of lines than in C++ This doesn't match reality. In reality, many Python projects have w

• BiteCode_dev 7y ago
  > many Python projects have way more lines of code than equivalent C++ projects. That is mathematically impossible. Even if the syntaxes were exactly the same (which they are not, python syntax is on average shorter), the low level nature of C++ requires your code to do operations that Python does need to do, such as memory management. It's like stating the sky is red.
  • snovv_crash 7y ago
    Once you've written sufficient unit tests to prove your code works as well as a C++ equivalent does just by compiling, I don't think Python ends up being more dense though. I'd also argue that operator overloading etc lets C++ be just as expressive as Python, the libraries just need to be designed with that in mind.
    • BiteCode_dev 7y ago
      > Once you've written sufficient unit tests to prove your code works as well as a C++ equivalent does just by compiling You mean in the same way C++ dev write tests to prove that all their code has no memory error which you get in Python for free ? Except: - tests are way shorter to write in python than in C++ - C++ devs often write zero tests for their code, just like python devs - python duck typing + REPL means compiler checks are rarely necessary - if you need to be type checks, you use type hints in python, which even then is still less verbose than c++ > I'd also argue that operator overloading etc lets C++ be just as expressive as Python, the libraries just need to be designed with that in mind. Ok, let's say you have this json: [{ "name": "Kévin", "age": 23, "hired": "2005-06-03 02:12:33", "emails": ["kevin@foo.com", "kevin@bar.com"] }, { }, { "name": "Joël", "age": 32, "hired": "2003-01-02 12:32:11", "emails": ["joel@foo.com", "joel@bar.com"] }, ... other entries ] It's very simple. Very basic. There is no trick in there: it's standard utf8, well formed, no missing value. You want to print people details in alphabetical order this way: Joël (32) - 02/01/03: - joel@foo.com - joel@bar.com Kévin (23) - 03/06/05: - kevin@foo.com - kevin@bar.com ... other entries This is a 1rst year of college exercise. Nothing remotely complicated. I'm not choosing some fancy machine learning or data processing stuff for which Python has magic libs. Every language can do that easily. In Python 3.7, which is already 2 years old, the code would be: import json import datetime as dt with open("agenda.json") as fd: agenda = sorted(json.load(fd), key=lambda people: people["name"]) for people in agenda: hired = dt.datetime.fromisoformat(people["hired"]) print(f'{people["name"]} ({people["age"]}) - {hired:%d/%m/%y}:') for email in people["emails"]: print(f" - {email}") The entire script is there. There is no trick. This is not a code golf version of of it; I could make it shorter. It really is standard Python. There is no 3rd party lib either. It's not specific to Python, you would get this expressiveness with Ruby or Perl. I don't see in which world you would get that in regular, honest to god, day to day, portable C++. You have to declare types, many includes, you'll have headers and a main function. You have the memory and references to manage. It doesn't make C++ a bad language. It doesn't make python a better language. The C++ version will take way less RAM than the Python version for example. It's just the nature of those languages implies that.
      • steveklabnik 7y ago
        For fun, I whipped this up in Rust. I decided to go with an explicit struct to serialize it into, because it makes the error handling easier, and is a bit more idiomatic. I kept unwrap because it's similar to the python semantic of throwing an exception. It's pretty close though! use chrono::NaiveDateTime; use serde::*; use serde_json; #[derive(Deserialize)] struct Person { name: String, age: u32, hired: String, emails: Vec<String>, } fn main() { let data = std::fs::read_to_string("agenda.json").unwrap(); let mut people: Vec<Person> = serde_json::from_str(data).unwrap(); people.sort_by(|a, b| b.name.cmp(&a.name)); for person in &people { let datetime = NaiveDateTime::parse_from_str(&person.hired, "%Y-%m-%d %H:%M:%S").unwrap(); println!( "{} ({}) - {}", person.name, person.age, datetime.format("%d/%m/%y") ); for email in &person.emails { println!(" - {}", email); } } }
        • BiteCode_dev 7y ago
          And Rust is very, very expressive and concise for a bare metal language. Serde is a beautiful thing.
        • steveklabnik 7y ago
          Apparently you can deserialize the date directly with serde and chrono too! So this could be even shorter.
      • jcelerier 7y ago
        It's a bit longer in C++ but frankly not by that much : #include <iostream> #include <sstream> #include <fstream> #include <iomanip> #include <nlohmann/json.hpp> #include <range/v3/action/sort.hpp> int main() { using namespace nlohmann; using namespace ranges; const json parsed = json::parse(std::ifstream("/tmp/json/test.json")); std::vector agenda(parsed.begin(), parsed.end()); sort(agenda, {}, [] (const auto& j) { return j["name"]; }); for(const auto& people : agenda) try { std::tm t{}; std::istringstream(people["hired"].get<std::string>()) >> std::get_time(&t, "%Y-%m-%d %H:%M:%S"); std::cout << people["name"] << " (" << people["age"] << ") - " << std::put_time(&t, "%d/%m/%y") << ": \n"; for(const auto& email : people["emails"]) std::cout << " - " << email << "\n"; } catch (...) { } }