How to print a number using commas as thousands separators

Slightly expanding the answer of Ian Schneider:

If you want to use a custom thousands separator, the simplest solution is:

'{:,}'.format(value).replace(',', your_custom_thousands_separator)

Examples

'{:,.2f}'.format(123456789.012345).replace(',', ' ')

If you want the German representation like this, it gets a bit more complicated:

('{:,.2f}'.format(123456789.012345)
          .replace(',', ' ')  # 'save' the thousands separators 
          .replace('.', ',')  # dot to comma
          .replace(' ', '.')) # thousand separators to dot

Here are some ways to do it with formatting (compatible with floats and ints)

num = 2437.68

# Way 1: String Formatting

'{:,}'.format(num)
>>> '2,437.68'


# Way 2: F-Strings

f'{num:,}'
>>> '2,437.68'


# Way 3: Built-in Format Function

format(num, ',')
>>> '2,437.68'

The accepted answer is fine, but I actually prefer format(number,','). Easier for me to interpret and remember.

https://docs.python.org/3/library/functions.html#format

Universal solution

I have found some issues with the dot separator in the previous top voted answers. I have designed a universal solution where you can use whatever you want as a thousand separator without modifying the locale. I know it's not the most elegant solution, but it gets the job done. Feel free to improve it !

def format_integer(number, thousand_separator='.'):
    def reverse(string):
        string = "".join(reversed(string))
        return string

    s = reverse(str(number))
    count = 0
    result = ''
    for char in s:
        count = count + 1
        if count % 3 == 0:
            if len(s) == count:
                result = char + result
            else:
                result = thousand_separator + char + result
        else:
            result = char + result
    return result


print(format_integer(50))
# 50
print(format_integer(500))
# 500
print(format_integer(50000))
# 50.000
print(format_integer(50000000))
# 50.000.000

Use separators and decimals together in float numbers : (In this example, two decimal places)

large_number = 4545454.26262666
print(f"Formatted: {large_number:,.2f}")

Result: Formatted: 4,545,454.26

babel module in python has feature to apply commas depending on the locale provided.

To install babel run the below command.

pip install babel

usage

format_currency(1234567.89, 'USD', locale='en_US')
# Output: $1,234,567.89
format_currency(1234567.89, 'USD', locale='es_CO')
# Output: US$ 1.234.567,89 (raw output US$\xa01.234.567,89)
format_currency(1234567.89, 'INR', locale='en_IN')
# Output: ₹12,34,567.89

this is baked into python per PEP -> https://www.python.org/dev/peps/pep-0378/

just use format(1000, ',d') to show an integer with thousands separator

there are more formats described in the PEP, have at it