假设我有一个值15.7784514，我想把它显示为15.77，没有舍入。
var num = parseFloat(15.7784514);
document.write(num.toFixed(1)+"<br />");
document.write(num.toFixed(2)+"<br />");
document.write(num.toFixed(3)+"<br />");
document.write(num.toFixed(10));
结果:
15.8
15.78
15.778
15.7784514000
如何显示15.77?
当前回答
这对我来说很有效。我希望它也能解决你的问题。
function toFixedNumber(number) {
const spitedValues = String(number.toLocaleString()).split('.');
let decimalValue = spitedValues.length > 1 ? spitedValues[1] : '';
decimalValue = decimalValue.concat('00').substr(0,2);
return '$'+spitedValues[0] + '.' + decimalValue;
}
// 5.56789 ----> $5.56
// 0.342 ----> $0.34
// -10.3484534 ----> $-10.34
// 600 ----> $600.00
function convertNumber(){ var result = toFixedNumber(document.getElementById("valueText").value); document.getElementById("resultText").value = result; } function toFixedNumber(number) { const spitedValues = String(number.toLocaleString()).split('.'); let decimalValue = spitedValues.length > 1 ? spitedValues[1] : ''; decimalValue = decimalValue.concat('00').substr(0,2); return '$'+spitedValues[0] + '.' + decimalValue; } <div> <input type="text" id="valueText" placeholder="Input value here.."> <br> <button onclick="convertNumber()" >Convert</button> <br><hr> <input type="text" id="resultText" placeholder="result" readonly="true"> </div>
其他回答
所有这些答案似乎都有点复杂。我只需从你的数字中减去0.5，然后使用toFixed()。
function FixWithoutRounding(number, digits) {
var gbZero = '0000000000';
var subNumber = number.toString().split('.');
if (subNumber.length === 1)
return [subNumber[0], '.', '0000'].join('');
var result = '';
if (subNumber[1].length > digits) {
result = subNumber[1].substring(0, digits);
} else {
result = subNumber[1] + gbZero.substring(0, digits - subNumber[1].length);
}
return [subNumber[0], '.', result].join('');
}
这些解决方案确实有效，但对我来说似乎没有必要这么复杂。我个人喜欢用模运算符来得到除法运算的余数，然后去掉余数。假设num = 15.7784514:
num-=num%.01;
这相当于说num = num - (num % .01)。
const toFixed = (value) => value. tostring ().slice(0,5);
我的解决方案在typescript(可以很容易地移植到JS):
/**
* Returns the price with correct precision as a string
*
* @param price The price in decimal to be formatted.
* @param decimalPlaces The number of decimal places to use
* @return string The price in Decimal formatting.
*/
type toDecimal = (price: number, decimalPlaces?: number) => string;
const toDecimalOdds: toDecimal = (
price: number,
decimalPlaces: number = 2,
): string => {
const priceString: string = price.toString();
const pointIndex: number = priceString.indexOf('.');
// Return the integer part if decimalPlaces is 0
if (decimalPlaces === 0) {
return priceString.substr(0, pointIndex);
}
// Return value with 0s appended after decimal if the price is an integer
if (pointIndex === -1) {
const padZeroString: string = '0'.repeat(decimalPlaces);
return `${priceString}.${padZeroString}`;
}
// If numbers after decimal are less than decimalPlaces, append with 0s
const padZeroLen: number = priceString.length - pointIndex - 1;
if (padZeroLen > 0 && padZeroLen < decimalPlaces) {
const padZeroString: string = '0'.repeat(padZeroLen);
return `${priceString}${padZeroString}`;
}
return priceString.substr(0, pointIndex + decimalPlaces + 1);
};
测试用例:
expect(filters.toDecimalOdds(3.14159)).toBe('3.14');
expect(filters.toDecimalOdds(3.14159, 2)).toBe('3.14');
expect(filters.toDecimalOdds(3.14159, 0)).toBe('3');
expect(filters.toDecimalOdds(3.14159, 10)).toBe('3.1415900000');
expect(filters.toDecimalOdds(8.2)).toBe('8.20');
任何改善吗?
