Controlling other aspects of the string

Not only does format() control the way the number is represented, it also controls some of the properties of the resulting string that affect its display.

For example, by default format() will pad the start of the strings with spaces so that the decimal points line up, which is really useful if you are presenting the numbers in a vertical column. However, if you are putting the number in the middle of a sentence, you might not want these extra spaces. You can set trim = TRUE to remove them.

When numbers are long it can be helpful to "prettify" them, for example instead of 1000000000 display 1,000,000,000. In this case a , is added every 3 digits. This can be controlled by the big.interval and big.mark arguments, e.g. format(1000000000, big.mark = ",", big.interval = 3, scientific = FALSE). These arguments are actually passed on to prettyNum() so head there for any further details.

This exercise is part of the course

String Manipulation with stringr in R

View Course

Exercise instructions

We've assigned your formatted income from the previous exercise to formatted_income.

Print formatted_income Notice the spaces at the start of the strings.
Call writeLines() on the formatted income. Notice how the numbers line up on the decimal point.
Define trimmed_income by using format() on income with digits = 2 and trim = TRUE.
Call writeLines() on trimmed_income. Notice how this removes the spaces at the start of the strings and the values line up on left.
Define pretty_income by using format() on income with digits = 2 and big.mark = ",".
Call writeLines() on pretty_income.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

formatted_income <- format(income, digits = 2)

# Print formatted_income
___

# Call writeLines() on the formatted income
___

# Define trimmed_income
___

# Call writeLines() on the trimmed_income
___

# Define pretty_income
___

# Call writeLines() on the pretty_income
___

Edit and Run Code