sprintf()

sprintf(fmt, ...)

sprintf() formats strings using C-style format specifiers. It takes a format string containing placeholders and substitutes values into them.

Syntax

sprintf(fmt, ...)

Parameters

Parameter	Type	Default	Description
fmt	character	—	Format string containing format specifiers
...	any	—	Values to substitute into the format string

Format Specifiers

The key format specifiers are:

Specifier	Meaning	Example
%s	String	"%s"
%d	Integer	"%d"
%f	Fixed-point number	"%.2f"
%e	Scientific notation	"%e"
%%	Literal percent sign	"%%"

Examples

Basic string substitution

sprintf("Hello, %s!", "World")
# [1] "Hello, World!"

name <- "Alice"
sprintf("Welcome, %s!", name)
# [1] "Welcome, Alice!"

Numeric formatting

sprintf("The value is %d", 42)
# [1] "The value is 42"

sprintf("Pi to 3 decimals: %.3f", pi)
# [1] "Pi to 3 decimals: 3.142"

sprintf("Scientific: %e", 1234)
# [1] "Scientific: 1.234000e+03"

Multiple values

sprintf("%s has %d points", "Player", 100)
# [1] "Player has 100 points"

sprintf("Item: %s, Price: $%.2f, Qty: %d", "Widget", 19.99, 5)
# [1] "Item: Widget, Price: $19.99, Qty: 5"

Padding and width

sprintf("%10s", "test")
# [1] "      test"

sprintf("%05d", 42)
# [1] "00042"

Common Patterns

Building file paths

filename <- "data"
extension <- "csv"
sprintf("%s.%s", filename, extension)
# [1] "data.csv"

Creating messages

n <- 150
total <- 500
sprintf("Processed %d of %d items (%.1f%%)", n, total, n/total*100)
# [1] "Processed 150 of 500 items (30.0%)"

Dynamic labels

sprintf("Iteration %03d complete", 5)
# [1] "Iteration 005 complete"

See Also

• base::paste
• base::paste0
• base::cat
• stringr::format