How to round up/down an int in Python?

Let’s say I have an arbitrary integer 874,623,123 how do I round it down to 800,000,000 and up to 900,000,000? Another example is 759 round up to 800 or down to 700. The size of the integer is unknown.

Is there a built-in method to do it? If not, what’s the best way to work it out? Sorry not a math expert here.

EDIT: So far I have looked at

Rounding down integers to nearest multiple

Python round up integer to next hundred

Both use a predefined divider

Answer

You can use the math module:

import math

n = 874623123

# c contains the same number of digits as n
c = 10 ** int(math.log10(n))

print(math.floor(n/c) * c) # 800000000
print(math.ceil(n/c) * c)  # 900000000