Which integer is easier to read: 100000000 or 100,000,000?

If you are human then you likely agree that the comma-separated 100,000,000 is more readable. Using the underscore (_) as a separator we can make integers more intuitive in Python.

# Non-readable integer. I can't easily tell if this is 100 million or 1 billion.
i = 100000000
print(i)
# Output:
# 100000000

# Readable integer. It is immediately obvious this is 100 million.
i = 100_000_000
print(i)
# Output:
# 100000000

While the code above is much more readable, the print statement still outputs the integer in it's non-readable form. Read below to see what we can do about that.

Formatting integers with f-strings

Python f-strings provide a way make printing or logging integers just as readable.

i = 100_000_000
print(f"{i:,}")
# Output:
# 100,000,000

# You can also provide the underscore as a separator if that's what you'd prefer.
i = 100_000_000
print(f"{i:_}")
# Output:
# 100_000_000

For more on all you can do with Python f-strings check out this great article by Martin Heinz, Python f-strings Are More Powerful Than You Might Think.