printf Function, formatted output - Perl String Tutorials

Tutorials

Perl

Topic

What is printf Function in Perl?

Explanation

This function is used to have a formatted output from a list.

Syntax:

    printf FILEHANDLE FORMAT, LIST
    printf FORMAT, LIST

The following are the formatting conversions that can be used.

Character	Description
%%	a percent sign
%c	a character with the given number
%s	a string
%d	a signed integer, in decimal
%u	an unsigned integer, in decimal
%o	an unsigned integer, in octal
%x	an unsigned integer, in hexadecimal
%e	a floating-point number, in scientific notation
%f	a floating-point number, in fixed decimal notation
%g	a floating-point number, in %e or %f notation
%X	like %x, but using upper-case letters
%E	like %e, but using an upper-case "E"
%G	like %g, but with an upper-case "E" (if applicable)
%p	a pointer outputs the Perl value's address in hexadecimal
%n	the number of characters output so far into the next variable

Perl also supports the following flags to get a formatted output.

Flag	Result
space	prefix positive number with a space
+	prefix positive number with a plus sign
-	left-justify within the field
0	use zeros, not spaces, to right-justify
#	ensure the leading "0" for any octal, non-zero hexadecimal with "0x" or "0X",non-zero binary with "0b" or "0B"

Example:

    #! C:\programfiles\perl\bin\perl
    print "content-type: text/html\n\n";
    printf("Decimal Number is: %d", 234.00);
    print "<br>";
    printf("Floating Point Number: %f",234.55);
    print "<br>";
    printf("Binary value of decimal 2: %b",2);   
    print "<br>";

Result:

    Decimal Number is: 234
    Floating Point Number: 234.550000
    Binary value of decimal 2: 10

In the above example printf Function, the floating point number is printed as a decimal number, in the second example the floating point number is rounded to 6 decimal places, in the third example the binary value of "2" is printed as "10".