Advanced Formatting: Float, Round, and PercentAdvanced Formatting: Float, Round, and Percent

Within a simple {} block, we can round a float number with the necessary precision, or represent a number as a percent.

Let's consider the pattern we will use in this chapter:

{:[thousands separator].[number][type]}

Please note, that like in the previous chapters, we don't need to place square brackets (I placed it for convenience).

  • [thousands separator] - the symbol used to separate every thousand (possible values are , and _).
  • [number] - is the precision, number of decimal places (used for rounding number).
  • [type] - type of number representing (e - scientific notation, % - percentage (will multiply number by 100), g - general format, f - fixed-point notation). You can dive deeper into possible options in Python documentation.


As of 2020, the population of the USA was 331002651. The total land area is 9147420 Population density is the population-to-area ratio. Your tasks are:

  1. Format the first string so the population and area will be printed in format: 9,147,420, and insert variables in the correct order.
  2. Within the second .format function calculate the population density and format the number in format 28.45.

Everything was clear?

Section 3. Chapter 8
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