literals

问题 I need some help figuring out how to execute this python code from python -c I am have trouble formatting python so that it will execute for another app in cmd I understand there maybe other ways to do what I am doing but I am limited by the final execution using cmd python -c so please keep this in mind. So I have some python code ie, import os import shutil myPath =r"C:\dingdongz" for root, dirs, files in os.walk(myPath): for file in files: os.remove(os.path(root, file)) for dir in dirs:

问题 I need some help figuring out how to execute this python code from python -c I am have trouble formatting python so that it will execute for another app in cmd I understand there maybe other ways to do what I am doing but I am limited by the final execution using cmd python -c so please keep this in mind. So I have some python code ie, import os import shutil myPath =r"C:\dingdongz" for root, dirs, files in os.walk(myPath): for file in files: os.remove(os.path(root, file)) for dir in dirs:

问题 Set literals were not supported until 2.2, How to set literals after Dart 2.2. Please feel free to comment. Thank you. class item_t { String name; int weight; int value; } main() { const List<item_t> items = [ {'map', 9, 1}, // reports errors ]; } update 1 I could define the list as a serial of define statements. However, it seems it is ineffective. class item_t { String name; int weight; int value; } main() { // final item_t items = new item_t(100); List<item_t> items = new List(2); items[0]

问题 At the moment I have a bunch of functions that check if strings meet certain circumstances eg isValidAlphaNumericString or isValidUserName. Which uses my own implicit stringOps class. It is quite useful especially when dealing with complex requirements such as author names etc. Requiring string to have only no consecutive -_. or space characters etc. Using complex regex's. But why stop there? The string isn't constrained properly meaning some function could map an anonymous function to it and

问题 This question already has answers here : What are the differences between Rust's `String` and `str`? (8 answers) Trying to declare a String const results in expected type, found “my string” (1 answer) Closed 2 years ago . I am trying to declare a const String in stable Rust but it does not let me declare it: const CONSTANT_VALUE: String = String::from("constant value"); fn main() { println!("{}", TARGET_PORT_KEY); } It is saying that: Calls in constants are limited to tuple structs and tuple

问题 This question already has answers here : What are the differences between Rust's `String` and `str`? (8 answers) Trying to declare a String const results in expected type, found “my string” (1 answer) Closed 2 years ago . I am trying to declare a const String in stable Rust but it does not let me declare it: const CONSTANT_VALUE: String = String::from("constant value"); fn main() { println!("{}", TARGET_PORT_KEY); } It is saying that: Calls in constants are limited to tuple structs and tuple

问题 This question already has answers here : What are the differences between Rust's `String` and `str`? (8 answers) Trying to declare a String const results in expected type, found “my string” (1 answer) Closed 2 years ago . I am trying to declare a const String in stable Rust but it does not let me declare it: const CONSTANT_VALUE: String = String::from("constant value"); fn main() { println!("{}", TARGET_PORT_KEY); } It is saying that: Calls in constants are limited to tuple structs and tuple

问题 This question already has answers here : What are the differences between Rust's `String` and `str`? (8 answers) Trying to declare a String const results in expected type, found “my string” (1 answer) Closed 2 years ago . I am trying to declare a const String in stable Rust but it does not let me declare it: const CONSTANT_VALUE: String = String::from("constant value"); fn main() { println!("{}", TARGET_PORT_KEY); } It is saying that: Calls in constants are limited to tuple structs and tuple

问题 Given the following code that does a reverse lookup on a map: map<char, int> m = {{'a', 1}, {'b', 2}, {'c', 3}, {'d', 4}, {'e', 5}}; int findVal = 3; Pair v = *find_if(m.begin(), m.end(), [findVal](const Pair & p) { return p.second == findVal; }); cout << v.second << "->" << v.first << "\n"; Is it possible to pass a literal value (in this case 3) instead of having to store it in a variable (i.e. findVal) so that it can be accessed via the capture list? Obviously one of the constraints in this

问题 Suppose i have something like int x = 2 + 3; Is x considered to be a literal? 回答1: x is a symbol. 2 + 3 is an expression. 2 and 3 are literals. 回答2: No, it's two literals in a compile-time constant expression. Depending on how it gets compiled, you may not be able to tell the difference in the resulting binary. 回答3: int - type of the variable, identifier x - name of the variable, identifier = - assignment 2 - literal + - operation between two literals 3 - literal ; - end of the statement 回答4: