Python format()

The format() method returns a formatted value based on the specified formatter.


value = 45

# format the integer to binary binary_value = format(value, 'b')
print(binary_value) # Output: 101101

format() Syntax

format(value, format_spec)

format() Parameters

The function takes two parameters:

  • value - the data we want to format
  • format_spec - the specification on how we want to format the data

format() Return Value

The format() function returns a value in the string representation of the desired format.

Example: Numeric Formatting Using format()

# decimal formatting decimal_value = format(123, 'd')
print("Decimal Formatting:", decimal_value)
# binary formatting binary_value = format(123, 'b')
print("Binary Formatting:", binary_value)


Decimal Formatting: 123
Binary Formatting: 1111011

Here, format(123, 'd') and format(123, 'b') converts the integer 123 to its decimal and binary string representation respectively.

Note: We have used format specifiers, d for decimal and b for binary. To learn more about format types, visit Format Types.

Number Formatting With Alignment and Width

Alignment in formatting refers to the way a number is positioned or placed within the available space, determining where it starts and ends in relation to that space.

It controls how the number is visually presented within a designated area.

Alignment options

Alignment Description
left-align < aligns the output string to the left
right-align > aligns the output string to the right
center-align ^ aligns the output string to the center of the remaining space

Let's look at an example.

# formatting numbers without specifying width no_width = format(123, 'd')
print("Without specified width:", no_width)
# formatting number with a width of 10, right-aligned right_aligned = format(123, '>10d')
print("Right-aligned with width 10:", right_aligned)
# formatting number with a width of 10, left-aligned left_aligned = format(123, '<10d')
print("Left-aligned with width 10:", left_aligned)
# formatting number with a width of 10, center-aligned center_aligned = format(123, '^10d')
print("Center-aligned with width 10:", center_aligned)


Without specified width: 123
Right-aligned with width 10:        123
Left-aligned with width 10: 123       
Center-aligned with width 10:    123  


  • format(123, 'd') - number is formatted without a specified width.
  • format(123, '>10d') - number is right-aligned within a 10-character width with extra space on the left.
  • format(123, '<10d') - number is left-aligned within a 10-character width with extra space on the right.
  • format(123, '^10d') - number is centered within a 10-character width with extra space evenly distributed on both sides.

Example: Number Formatting With Sign

# using '+' and '-' format specifier positive_with_plus = format(123, '+') positive_with_minus = format(123, '-')
print("Positive with '+':", positive_with_plus) print("Positive with '-':", positive_with_minus)


Positive with '+': +123
Positive with '-': 123

In the above example, we formatted the numbers 123 and -123 using each of the sign options.

The sign option in formatting controls the display of the sign for the numbers. Here, + indicates that both positive and negative numbers will show their signs.

Note: The sign option - indicates only negative numbers will show their sign and ' ' will show a space for positive numbers and a minus for negative numbers.

Example: Number Formatting With Precision

Precision allows us to define the number of digits to be shown after a decimal point. For example,

# set precision to 2 for floating-point number precision_value = format(123.4567, '.2f')
print(precision_value) # Output: 123.46

Here, .2f means two digits will be shown after the decimal point.

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