javascript 将百分比添加到数字
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Add percent to numbers
提问by Erik
How can I add percent to a sum? I have tried var sum = 3.25 + '3.4%';but it didn't work. I'm just getting 0.00as an answer.
如何将百分比添加到总和中？我试过了，var sum = 3.25 + '3.4%';但没有用。我只是得到0.00一个答案。
回答by Pointy
To "add a percent to a number" means "multiply the number by (1 + pct)":
“给数字加一个百分比”的意思是“将数字乘以(1 + pct)”：
var sum = 3.25;
sum = sum * (1 + 0.034);
You could equivalently skip the 1(that's just the way I think about it) and add:
您可以等效地跳过1（这只是我的想法）并添加：
var sum = 3.25;
sum += sum * 0.034;
So if you're starting off with a string representation of a percentage, you can use parseFloat()to make it a number:
因此，如果您开始使用百分比的字符串表示形式，则可以使用parseFloat()将其设为数字：
var pct = "3.4%"; // or from an <input> field or whatever
pct = parseFloat(pct) / 100;
The parseFloat()function conveniently ignores trailing non-numeric stuff like the "%" sign. Usually that's kind-of a problem, but in this case it saves the step of sanitizing the string.
该parseFloat()函数可以方便地忽略尾随的非数字内容，例如“%”符号。通常这是一个问题，但在这种情况下，它省去了清理字符串的步骤。
回答by Jason
String concatenation and number adding using the same + symbol. You need to use () around the numbers.
字符串连接和数字添加使用相同的 + 符号。您需要在数字周围使用 ()。
var sum = (3.25+3.4)+"%";
