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