Question

我有以下字符串 - 它们是赋值命令：

my_dict = dict(lnodenum = 134241, d1 = 0.200000, jobname = 'hcalfzp')

有没有办法将包含变量和值的字符串转换为字典的键和值？它等同于执行以下命令：

my_str = """lnodenum = 134241
            d1 = 0.200000
            jobname = 'hcalfzp' """
exec('my_dict = dict(%s)' % ','.join(my_str.split('\n')))

我想这是一种方法：

public static void main(String[] args){
    //Declares my input variables and Scanner variable
    String firstInput;
    String secondInput;
    String userProblem;
    char operator;
    //Creates the scanner
    Scanner userInput = new Scanner(System.in);

    //Asks for input
    System.out.println("Please enter a problem you would like to calculate (ex. \"2.0 * 4.3\")");
    userProblem = userInput.nextLine();

    //Finds the doubles in the string and the operator
    firstInput = userProblem.substring(0, 3);
    secondInput = userProblem.substring(6, 9);
    operator = userProblem.charAt(4);

    //parses the strings to doubles
    double firstNumber = Double.parseDouble(firstInput);
    double secondNumber = Double.parseDouble(secondInput);

    //Tests for the operator and executes accordingly
    if(operator == '+'){
        System.out.println(firstNumber + secondNumber);
    }
    else{
        if(operator == '-'){
            System.out.println(firstNumber - secondNumber);
        }
        else{
            if(operator == '*'){
                System.out.println(firstNumber * secondNumber);
            }
            else{
                if(operator == '/'){
                    System.out.println(firstNumber / secondNumber);
                }
                else{
                    if(operator == '%'){
                        System.out.println(firstNumber % secondNumber);
                    }
                    else{
                        System.out.println("You did not input correctly");
                    }
                }
            }
        }
    }
}

不确定是否有人会想到更简洁的方式？

注意：我正在使用自己的代码进行科学计算，所以我不介意使用像恶意输入数据这样的安全问题的代码。但是，我更喜欢让代码更短更容易阅读：）

Answer 1

不需要exec。只需使用dict函数的常规作业。

my_str = """lnodenum = 134241
            d1 = 0.200000
            jobname = 'hcalfzp' """
my_dict = dict(pair for pair in (line.strip().split(' = ') for line in my_str.splitlines()))

结果：

>>> my_dict
{'d1': '0.200000', 'lnodenum': '134241', 'jobname': "'hcalfzp'"}

或者，如果您想要解析每个对象，请使用ast.literal_eval并理解：

import ast
my_dict = {k:ast.literal_eval(v) for k,v in (line.strip().split(' = ') for line in my_str.splitlines())}

结果：

>>> my_dict
{'d1': 0.2, 'lnodenum': 134241, 'jobname': 'hcalfzp'}

在Python中将赋值字符串转换为dicts

1 个答案: