How to print a number using commas as thousands separators

Adapting to different Python versions

Different Python versions may require different formatting approaches:

For Python 2.7 through 3.5, you can use the format() method:

print("{:,}".format(1000000))  # It's like a party, but the guests are commas!
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Outputs: 1,000,000

For versions prior to Python 3.6, you can use the format() function directly:

print(format(1234567, ","))  # Remember, you "comma" here often!
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Outputs: 1,234,567

Leveraging built-in formatting capabilities

Python offers some sophisticated built-in formatting methods that you might find useful:

Taking locale into account

Sometimes, you need to respect local customs, even in programming!

import locale
locale.setlocale(locale.LC_ALL, 'en_US.UTF-8')
print(locale.format_string("%d", 1000000, grouping=True))  # Print money the American way!
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Outputs: 1,000,000

Developer-friendly formatting with underscores

Spice it up with some underscores for the ultimate developer swag:

print(f"{0b1010101010:_b}")  # Because who needs commas when you got underscores!
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Outputs: 10_1010_1010

Tailoring a custom function

When the built-in methods seem too mainstream for you, go custom with intWithCommas.

Introducing the intWithCommas function

def intWithCommas(x):
    if x < 0:
        return '-' + intWithCommas(-x)
    result = str(x)
    while len(result) > 3:
        result = f"{result[:-3]},{result[-3:]}"  # Hand-picked, artisanal commas at just the right spots!
    return result

print(intWithCommas(1000000))
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Outputs: 1,000,000

Solving tricky scenarios

Getting the commas right sometimes needs a little more care:

Handling negatives like a boss

Negatives got you down? With Python, you can flip them around!

formatted_number = intWithCommas(-1234567).replace("-", "–")  # Minus, meet comma. You two play nice!
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Keeping performance in check

Your program's not a speedster? Let's streamline it!

# Not recommended
#print(','.join(str(1000000)[i:i+3] for i in range(0, len(str(1000000)), 3)))  # Way too many loo-loops for a simple comma!

# Clear and maintainable
print(intWithCommas(1000000))  # Oldie but a Goldie!
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