How to print number with commas as thousands separators?

Locale unaware

'{:,}'.format(value)  # For Python ≥2.7
f'{value:,}'  # For Python ≥3.6

Locale aware

import locale
locale.setlocale(locale.LC_ALL, '')  # Use '' for auto, or force e.g. to 'en_US.UTF-8'

'{:n}'.format(value)  # For Python ≥2.7
f'{value:n}'  # For Python ≥3.6

Reference

Per Format Specification Mini-Language,

The ',' option signals the use of a comma for a thousands separator. For a locale aware separator, use the 'n' integer presentation type instead.