Question

我希望能够限制从打印功能显示的小数位数，而不需要任何类型的舍入系统

v = 8.836333333333339

print（'％。2f'％v）

此代码会将v的值打印到两个小数位，但也会向上或向下舍入，我怎么能让它停止这个舍入呢？

Answer 1

您可以将其作为字符串处理：

v = 8.836333333333339
s = str(v)
print s[:s.find('.')+3]

# prints 8.83

Answer 2

如果您知道该数字的长度，您可以使用字符串切片轻松完成此操作。

>>> v = 8.836333333333339
>>> x = str(v) # get string representation of 'v'
>>> x
'8.836333333333339'

>>> y = x[0:4] # every character in 'x' between 0 and 4 but not including 4
>>> y
'8.83'

>>> v = float(y) # you can even convert it back to a number if you want
>>> v
8.83

Answer 3

使用十进制模块怎么样：

>>> help(Decimal.quantize)
Help on method quantize in module decimal:

quantize(self, exp, rounding=None, context=None, watchexp=True) unbound decimal.Decimal    
method
    Quantize self so its exponent is the same as that of exp.

Similar to self._rescale(exp._exp) but with error checking.


>>> from decimal import *
>>> v = 8.834333333333339
>>> print Decimal(v).quantize(Decimal('0.01'))
8.83
>>> print Decimal('8.8663').quantize(Decimal('0.01'))
8.87 
>>> print Decimal('8.863').quantize(Decimal('0.01'))
8.86
>>>

Answer 4

有点针对您的情况，但您也可以使用int来截断：

 >>> print(int(v*100)/100.0)
 8.83

它比基于find字符串的方法快3倍（310 ns vs 925 ns）。

Answer 5

private void button2_Click(object sender, EventArgs e)
    {
        int X = 153;
        int Y = 34;
        for (int i = 1; i < 4; i++)
        {
            Panel pnl = new Panel();
            pnl.SuspendLayout();
            pnl.Location = new Point(X, Y);
            pnl.Name = "pnl"+i;
            pnl.Size = new Size(200, 57);
            pnl.BorderStyle = BorderStyle.FixedSingle;

            Label lbl = new Label();
            lbl.Location = new Point(X - 100, Y - 17);
            lbl.Name = "lbl" + i;
            lbl.Size = new Size(75, 23);
            lbl.Text = "lable_" +i;

            pnl.Controls.Add(lbl);
            pnl.ResumeLayout(false);

            this.Controls.Add(pnl);

            Y = Y + 95;
        }
    }

why not display label2 & label3?

如何在不舍入的情况下限制显示一定数量的小数位？

5 个答案: