如何使用JavaScript总结独特的价值 [英] How to sum up distinct value using javascript

问题描述

我想尝试从列表中总结出明显的价值..如果只有2条相似的记录，我现在能够做到.如果超过2，我将无法进行检查.以下是JavaScript代码:

I want to try and sum up distinct value from a list.. currently i am able to do so if theres only 2 similar record. If theres more than 2 i am not able to do the checking. Following is the javascript code:

function validateData(){
    var total = document.frm.size.value;
    var msg="";
    var tbxA;
    var tbxB;
    var tbxA2;
    var tbxB2;
    var tbxC;
    var totalValue =0;
    var repeatedValue= 0;
    var row = 0;      
    var row2 = 0;   

    for(var i=0; i<parseInt(total); i++){
        tbxA = document.getElementById('tbx_A'+i).value;
        tbxB = document.getElementById('tbx_B'+i).value-0;
        tbxC = document.getElementById('tbx_C'+i).value;
        for(var j=i+1; j<parseInt(total); j++){
            tbxA2 = document.getElementById('tbx_A'+j).value;
            tbxB2 = document.getElementById('tbx_B'+j).value-0;

            if (tbxA==tbxA2) {
                totalValue = tbxB + tbxB2;
            }
                if (totalValue != tbxC) {
                    repeatedValue= 1;
                    row = i;
                    row2 = j;
                    msg+="*total value  does not add up at row " +(row2+1);
                    break;
                }
        }
        if(repeatedValue== 1){  
        break;
        }
    }
    return msg;
}

例如A:水果的类型，B:每种水果的总和，C:一次购买的数量
C的总数应等于B.即Apple:3 + 3 + 4 =10.因此，如果总数不等于10，则会提示我一个错误.

For example A:type of fruit, B: total of each fruit, C: how many bought at a time
total of C should be equal to B. i.e Apple: 3+3+4 = 10. So if the total is not equals to 10 it should prompt me an error.

 A       B     C
 Apple   10    3
 Orange  10    10
 Apple   -     3
 Apple   -     4

我上面的代码将提示错误bt，它不会超出Apple的第二次出现.
所以，是的，我应该如何确保它遍历整个列表以总结所有相似的值?

My code above will prompt error bt it doesnt go beyond 2nd occurence of Apple.
So yes, how should i go about to ensure it loop through the whole list to sum up all similar values?

在此先感谢您提供任何帮助！

Thanks in advance for any possible help!

推荐答案

尝试一下:

var total = +document.frm.size.value,
    data = {};
for(var i=0; i<total; ++i) {
    var key = document.getElementById('tbx_A'+i).value;
    data[key] = data[key] || {B:0, C:0};
    data[key].B += +document.getElementById('tbx_B'+i).value || 0;
    data[key].C += +document.getElementById('tbx_C'+i).value || 0;
}
for(var i in data) {
    if(data.hasOwnProperty(i) && data[i].B != data[i].C) {
        return "total value does not add up";
    }
}
return "";

一些评论:

• parseInt(和parseFloat)非常慢.字符串之前的+运算符将其更快地转换为数字.但是，如果您真的想确保数字是整数，请使用Math.floor()，Math.round()，Math.ceil()或更快但难以辨认的|0.
• 如果您确实想要parseInt(例如，要将'123foobar'转换为123)，请始终使用基数.例如:parseInt('123', 10)
• 避免在循环条件下进行计算，因为它们在每次迭代时运行.只需在循环之前进行一次计算，然后将结果保存在变量中即可.

• parseInt (and parseFloat) is very slow. + operator before string converts it to a number much faster. But if you really want to make sure the numbers are integers, use Math.floor(), Math.round(), Math.ceil() or the faster but illegible |0.
• In case you really want parseInt (e.g. you want to convert '123foobar' into 123), always use a radix. For example: parseInt('123', 10)
• Avoid doing calculations at the condition of a loop, because they run at each iteration. Just do the calculation once before the loop and save the result in a variable.

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