Ruby Programming Language

Formatted Output

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First published on August 23, 2019. Last updated on February 13, 2020.


There are ways to more nicely format screen output for Ruby. Typically, we will create a statement that will tell Ruby to format output into columns of specified sized. We can also use tabs to align the columns. Below is an example of code to nicely-formatted output.

The trick to nicely-formatted output is to create a string expression with formatting information. Below, that expression is to the right of the periodstringvariable. Here is what each part does:

  • %2d produces a fixed number column with a width of 2.
  • \t tabs the output to the right.
  • %11.3f creates a floating number column that is eleven characters wide with three digits after the decimal place.

The puts sprintfcode then prints the variables to its right using the format expression. Note: the number of columns in the expression must match the number of variables after sprintf.

[code lang=”ruby”]
# display variables with type conversions
per = period.to_s
lin = lineargrowth.to_s
exp = exponentialgrowth.to_s
periodstring = (”%2d\t\t%11.3f\t\t%1.3f”)
puts sprintf periodstring , per , lin ,exp
[/code]

It can be difficult to fit the full variable names after the sprintf command without going to another line. So short versions of the variable names are created, such as:

 per, lin, exp.

The above code will produce output in formatted, consistently-spaced columns.


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