String formatting with sprintf in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the sprintf function do in R?

It creates a formatted string by inserting values into a template, similar to filling blanks in a sentence.

beginner

How do you format a number to show exactly 2 decimal places using sprintf?

Use %.2f in the format string, like sprintf("%.2f", 3.14159) which outputs "3.14".

beginner

What does the format specifier %d mean in sprintf?

It means to format the value as an integer (whole number).

intermediate

How can you include a literal percent sign (%) in the output of sprintf?

Use %% in the format string to print a single percent sign.

intermediate

What happens if you provide more values than format specifiers in sprintf?

Extra values are ignored; only values matching the format specifiers are used.

Which sprintf format specifier would you use to format a floating-point number with 3 decimal places?

A %.3d

B %d

C %s

D %.3f

The %.3f specifier formats a number as a float with 3 decimal places.

What will sprintf("Hello %s", "world") output?

A Hello %s

B Hello world

C world Hello

D Error

The %s is replaced by the string "world", so the output is "Hello world".

How do you print a percent sign (%) using sprintf?

A Use %%

B Use %p

C Use %s

D Use %percent

Double percent signs (%%) print a single percent sign in the output.

What does sprintf("%d", 3.7) output?

A 4

B 3.7

C 3

D Error

The %d specifier converts the number to an integer by truncating the decimal part.

If you have fewer values than format specifiers in sprintf, what happens?

A Error or warning

B It fills missing values with zero

C It ignores missing values

D It repeats last value

Missing values for format specifiers cause an error or warning because sprintf expects matching values.

Explain how to use sprintf to format a string with a name and a number showing two decimals.

Think about placeholders for text and numbers.

Describe how to print a literal percent sign (%) using sprintf and why it requires special syntax.

Percent signs are used to mark placeholders.