Question

我试图从javascript中的字符串中提取多项式字符串的不同部分，如变量，系数和幂。到目前为止，我能够从一个简单的多项式字符串中提取它们，例如“-13x ^ 2 + 2-12x ^ 4”。

我想将其扩展为从相对复杂的多项式字符串中提取。类似于“-13x ^ 2y ^ 3 + 2-12x ^ -4”。

以下是我的代码：

function extractPolynomial(polynomialStr) {
    var arr = [];
    polynomialStr = polynomialStr.match(/[+-]?\d+(x|y)(\^\d)*|[+-\s]\d+/g);
    polynomialStr.forEach(function (match) {
        var vals = match.split('^');
        var coeff = parseInt(vals[0]);
        var variable = vals[0].match(/[a-z]/gi) ? vals[0].match(/[a-z]/gi)[0] : "";
        var power = 1;
        if(vals.length > 1){
            power = parseInt(vals[1]);
        }
        else {
            if (variable === "") {
                power = 0;
            }
            else {
                power = 1;
            }
        }
        arr.push({
            coeff: coeff,
            variable: variable,
            power: power
        })
    });
    return arr;
}

这是小提琴：https://jsfiddle.net/889ruq7a/

Answer 1

通过对正则表达式的一些研究，我得到了我想要的东西。以下是从多项式中提取所有信息的函数：

function  extractPolynomial(polynomialStr) {        
    var arr = [];
    polynomialStr = polynomialStr.match(/[+-]?\d*(x|y)(\^\d)*((y|x)(\^\d)*)*|[+-\s]\d+/g);
    polynomialStr.forEach(function (match) {
        var variable = match.match(/([a-z]\^\d|[a-z])/gi) ? match.match(/([a-z]\^\d|[a-z])/gi).join("") : " ";
        var coeff = parseFloat(match.split(variable)[0]);
        var power = 1;
        var variables = [];
        if (variable != " ") {
            var tempVars = variable.match(/([a-z]\^\d|[a-z])/gi);
            for (var i = 0; i < tempVars.length; i++) {
                var oneVariable = { variable: "", power: 0 };
                oneVariable.variable = tempVars[i].match(/[a-z]/gi)[0];
                var tempV = tempVars[i].split("^");
                if (tempV.length > 1) {
                    oneVariable.power = parseFloat(tempV[1]);
                }
                else {
                    oneVariable.power = 1;
                }
                variables.push(oneVariable);
            }
        }
        else {
            variables.push({ variable: "", power: 0 });
        }
        arr.push({
            coeff: coeff,
            variables: variables
        });
    });
    return arr;
};

以下是它的小提琴：https://jsfiddle.net/khubaib/40hm80qu/5/

提取变量，Coeffcients＆amp;来自多项式字符串（Javascript）的权力

1 个答案: