问题
I have made a Python 3 program to calculate pi for a school project, but it always stops at 16 decimal places. Is there a limit to the length of numbers in python? If so is there a language that I could use that will let me continue?
accuracy = int(input("accuracy: "))
current = 2
opperation = "+"
number = 3
count = 1
for i in range (accuracy):
if opperation == "-":
number = number - (4/(current*(current+1)*(current+2)))
opperation = "+"
elif opperation == "+":
number = number + (4/(current*(current+1)*(current+2)))
opperation = "-"
current += 2
print(str(count).zfill(8)) + ": " + str(number)
count += 1
回答1:
There is no restriction if you are working with integers and Python 3.x. The precision you get using floating point numbers is however limited. A Python float
(like 3.14
) is really a C double
, which have about 16 decimals of precision, as you say.
You can use the decimal
module to create and work with other floating point numbers with arbitrary precision. Example code:
# Normal Python floats
a = 0.000000000000000000001
b = 1 + 2*a
print(b) # Prints 1.0
# Using Decimal
import decimal
decimal.getcontext().prec = 100 # Set the precision
a = decimal.Decimal('0.000000000000000000001')
b = 1 + 2*a
print(b) # Prints 1.000000000000000000002
See the docs for more information on decimal
.
来源:https://stackoverflow.com/questions/41553774/are-there-number-limitations-in-python