python保存两位小数的多种方法汇总

>>> x = 3.1415926
>>> print("%.2f" % x)
3.14
>>>

>>> x = 3.1415926
>>> round(x, 2)
3.14
>>>

def round(number, ndigits=None): # real signature unknown; restored from __doc__
    """
    round(number[, ndigits]) -> number
    
    Round a number to a given precision in decimal digits (default 0 digits).
    This returns an int when called with one argument, otherwise the
    same type as the number. ndigits may be negative.
    """
    return 0

>>> from decimal import Decimal
>>> x = 3.1415926
>>> Decimal(x).quantize(Decimal("0.00"))
Decimal('3.14')
>>> a = Decimal(x).quantize(Decimal("0.00"))
>>> print(a)
3.14
>>> type(a)
<class 'decimal.Decimal'>
>>> b = str(a)
>>> b
'3.14'

>>> x = 3.1415926
>>> str(x).split(".")[0] + "." + str(x).split(".")[1][:2]
'3.14'

>>> import re
>>> x = 3.1415926
>>> re.findall(r"\d{1,}?\.\d{2}", str(a))
['3.14']

num = '1234567'		#字符串num

print(num[:3])