Question

我的号码是15.579。我想格式化它写0.15790000E + 02。我可以将它显示为1.57900000E + 01，但我想要小数点前的0。我怎么能用Python做到这一点？

Answer 1

这应该有效。这会检查负数和任何奇怪的结果。我还使用了Python的默认精度，并使得小数点字符可以更改。如果您想要8个数字，可以轻松更改默认精度，如您的示例所示，但Python的默认值为6。

def alt_sci_notation(x, prec=6, decpt='.'):
    """Return a string of a floating point number formatted in
    alternate scientific notation. The significand (mantissa) is to be
    between 0.1 and 1, not including 1--i.e. the decimal point is
    before the first digit. The number of digits after the decimal
    point, which is also the number of significant digits, is 6 by
    default and must be a positive integer. The decimal point character
    can also be changed.
    """
    # Get regular scientific notation with the new exponent
    s = '{0:.{p}E}'.format(10 * x, p=prec-1)
    # Handle negative values
    prefix = ''
    if s[0] == '-':
        prefix = s[0]
        s = s[1:]
    # Return the string after moving the decimal point
    if prec > 1:  # if a decimal point exists in thesignificand
        return prefix + '0' + decpt + s[0] + s[2:]
    else:  # no decimal point, just one digit in the significand
        return prefix + '0' + decpt + s

以下是iPython中的示例结果。

alt_sci_notation(15.579, 8)
Out[2]: '0.15579000E+02'

alt_sci_notation(-15.579, 8)
Out[3]: '-0.15579000E+02'

alt_sci_notation(0)
Out[4]: '0.000000E+00'

alt_sci_notation(100000000)
Out[5]: '0.100000E+09'

alt_sci_notation(.00000001)
Out[6]: '0.100000E-07'

如何在python中格式化浮点数？

1 个答案: