from decimal import Decimal, ROUND_HALF_UP 1. rounding参数为ROUND_HALF_UP In [127]: Decimal("3.124").quantize(Decimal("0.00"), rounding=ROUND_HALF_UP) Out[127]: Decimal('3.12') In [128]: Decimal("3.125").quantize(Decimal("0.00"), rounding=ROUND_HALF_UP) Out[128]: Decimal('3.13'...
Learn how to round a number to 2 decimal places in Python for improved precision using techniques like round(), format(), and string formatting techniques.
import decimal context = decimal.getcontext() ROUNDING_MODES = [ 'ROUND_CEILING', 'ROUND_DOWN', 'ROUND_FLOOR', 'ROUND_HALF_DOWN', 'ROUND_HALF_EVEN', 'ROUND_HALF_UP', 'ROUND_UP', 'ROUND_05UP', ] header_fmt = '{:10} ' + ' '.join(['{:^8}'] * 6) print header_fmt.forma...
decimal是Python核心库用于实现高精度小数运算模块。对比原生的float类型,Decimal类型能更好地保证计算精度,特别是货币计算或涉及其他高精度计算的场景。 rounding参数取值ROUND_HALF_UP, from decimal import Decimal, ROUND_HALF_UP In [127]: Decimal("3.124").quantize(Decimal("0.00"), rounding=ROUND_HALF_UP) ...
>>> round(2.675,2) 2.67 机器中浮点数不一定能精确表达,因为换算成一串1和0后可能是无限位数的,机器已经做出了截断处理。那么在机器中保存的2.675这个数字就比实际数字要小那么一点点。这一点点就导致了它离2.67要更近一点点,所以保留两位小数时就近似到了2.67。
1、Python四舍五入,round函数用于精度没有要求的地方 整数及保留一位小数的时候使用round函数,可以正常四舍五入 2、decimal模块处理四舍五入,用于精度有要求的地方 Decimal.Context(prec=3,rounding=ROUND_HALF_UP).create_decimal(string类型)返回正常的四舍五入的答案 ...
python2和python3的doc中都举了个相同的例子,原文是这么说的: NoteThebehavior of round()forfloats can be surprising:forexample,round(2.675,2)gives2.67instead of the expected2.68.Thisisnota bug:it’s a result of the fact that mostdecimalfractions can’t be represented exactlyasafloat.SeeFloatingPoi...
called with one argument, otherwise of the same type as number.NoteThe behavior of round() for floats can be surprising: for example, round(2.675, 2) gives 2.67 instead of the expected 2.68. This is not a bug: it’s a result of the fact that most decimal ...
1)ROUND_UP:舍弃小数部分非0时,在前面增加数字,如 5.21 -> 5.3; 2)ROUND_DOWN:舍弃小数部分,从不在前面数字做增加操作,如5.21->5.2; 3)ROUND_CEILING:如果Decimal为正,则做ROUND_UP操作;如果Decimal为负,则做ROUND_DOWN操作; 4)ROUND_FLOOR:如果Decimal为负,则做ROUND_UP操作;如果Decimal为正,则做ROUND_...
print(round(3.447444, 2)) >>3.45 from decimal import Decimal print(Decimal('0.3') + Decimal('0.9')) >>1.2 import math #向上取