| Classification: | Perl 4 |
Perl 5 |
Syntax
printf(string, EXPRESSION) printf(FILE_VARIABLE, string, EXPRESSION)
Usage
The printf function has many of the same properties as the print function; however, it lets you better format your output. This is simply done by
placing a field specifier in your string passed followed by a comma-separated EXPRESSION. When the statement is printed to the screen or file, it will replace the field specifier with EXPRESSION in the specified format.
The following is a table of the formatting options along with a brief description of each:
| Option | Description |
|---|---|
| %c | Character |
| %d | Decimal number |
| %e | Scientific notation float |
| %f | Fixed-point float |
| %g | Compact float |
| %ld | Long decimal number |
| %lo | Long octal number |
| %lu | Long unsigned number |
| %lx | Long hexadecimal number |
| %o | Octal number |
| %s | String |
| %u | Unsigned decimal number |
| %X | Uppercase hexadecimal number |
| %x | Hexadecimal number |
Examples
This example defines a string and a numeric value in two variables. The printf function call passes a string and the field specifiers where the variables are then inserted to their locations before the string is printed:
# define the number and string
$num = 3456.4;
$string = ("Hello Perl World");
# prints 'The cost is $ 3456.40 and the
# string is Hello Perl World'
printf("The cost is \$%8.2f and the string is %s", $num, $string);
This example demonstrates how the printf function can write information to a file. Here I open a file in write mode and assign the string "Hello Perl World" to a variable. The printf function then takes the passed information and writes the informatio n to the file. The "string" field specifier, %s, is replaced with the value of $text when the information is written:
# open file for writing
open(OUT, "&lgt;test.txt") || die("Error: unable to open file\n");
#define the string
$text = ("Hello Perl World!\n");
# print text to that file via its handle
printf(OUT "The string is: %s", $text);
Parameters
expression
handle
string
Value
numeric
See Also:
open, print, sprintf, write