制作一个更精确的程序来计算（例如 2/3），而不仅仅是 16 个字符

Question

这是我的代码：def start():    #main input variable to get a sign to do    calculator = input('What would you like to calculate? (x, /, +, -): ')    #gets 2 #'s to multiply, add, subtract, or divide     if (calculator) == ('+'):        add = input('what is the frist number would you like to add? ')        addi = input('what is the second number would you like to add? ')    elif (calculator) ==('-'):        sub = input('what is the first number would you like to subtract? ')        subt = input('what is the second number you would like to subtract? ')    elif (calculator) == ('/'):        div = input('what is the first number would you like to divide? ')        divi = input('what is the second number would you like to divide? ')    elif (calculator) == ('x'):        mult = input('what is the first number would you like to multiply? ')        multi = input('what is the second number would you like to multiply? ')    #failsafe if done incorrect    elif (calculator) != ('x', '/', '-', '+'):        print('try again')        return    #adds 2 inputted #'s    if calculator == '+' :        sumAdd = float (add) + float (addi)        print(sumAdd)    #multiplies the 2 inputted #'s    elif calculator == 'x' :        sumMul =  float (mult) * float (multi)        print(sumMul)    #divides the 2 inputted #'s    elif calculator == '/' :        sumDiv = float (div) / float (divi)        print(sumDiv)    #subtracting the 2 inputted #'s    elif calculator == '-' :        sumSub = float (sub) - float (subt)        print(sumSub)    #returns to top of code to do another setup    returnstart()这很简单，我明白了。可以返回数字/整数，但我是从头开始做的，我很满意只是想知道如何在不做更多代码的情况下获得 16 位以上的小数。还要看看是否有比例如 (float) 或 (int) 更好的价值来完成这项工作。如果不是一切都很好，如果您有任何答案，请打开谢谢！

Answer 1

试试这个decimal模块：

from decimal import Decimal, getcontext

# set desired precision, 30 for example

getcontext().prec = 30

# normal

print(1 / 7)

# 0.14285714285714285

# with Decimal

print(Decimal(1) / Decimal(7))

# 0.142857142857142857142857142857

Answer 2

评论是正确的，format()是不准确的。

您可以使用十进制模块。

from decimal import *

getcontext().prec = 6 #set the number of decimals you prefer

Decimal(1) / Decimal(7)

>>> Decimal('0.142857')

getcontext().prec = 28

Decimal(1) / Decimal(7)

>>> Decimal('0.1428571428571428571428571429')