printf

Description
Syntax
Examples
Links

Description

The printf of String for PHP output a formatted string.

Syntax

printf(
    string $format,
    mixed ...$values
): int

The format string is composed of zero or more directives: ordinary characters (excluding %) that are copied directly to the result and conversion specifications, each of which results in fetching its own parameter.

A conversion specification follows this prototype: %[argnum$][flags][width][.precision]specifier.

Argnum

An integer followed by a dollar sign $, to specify which number argument to treat in the conversion.

Flags

Flag	Description
-	Left-justify within the given field width; Right justification is the default
+	Prefix positive numbers with a plus sign +; Default only negative are prefixed with a negative sign.
(space)	Pads the result with spaces. This is the default.
0	Only left-pads numbers with zeros. With s specifiers this can also right-pad with zeros.
'(char)	Pads the result with the character (char).

Width

An integer that says how many characters (minimum) this conversion should result in.

Precision

A period . followed by an integer who's meaning depends on the specifier:

For e, E, f and F specifiers: this is the number of digits to be printed after the decimal point (by default, this is 6).

For g and G specifiers: this is the maximum number of significant digits to be printed.

For s specifier: it acts as a cutoff point, setting a maximum character limit to the string.

Note: If the period is specified without an explicit value for precision, 0 is assumed.

Note: Attempting to use a position specifier greater than PHP_INT_MAX will generate warnings.

Specifier

Specifier	Description
%	A literal percent character. No argument is required.
b	The argument is treated as an integer and presented as a binary number.
c	The argument is treated as an integer and presented as the character with that ASCII.
d	The argument is treated as an integer and presented as a (signed) decimal number.
e	The argument is treated as scientific notation (e.g. 1.2e+2). The precision specifier stands for the number of digits after the decimal point since PHP 5.2.1. In earlier versions, it was taken as number of significant digits (one less).
E	Like the e specifier but uses uppercase letter (e.g. 1.2E+2).
f	The argument is treated as a float and presented as a floating-point number (locale aware).
F	The argument is treated as a float and presented as a floating-point number (non-locale aware).
g	General format. Let P equal the precision if nonzero, 6 if the precision is omitted, or 1 if the precision is zero. Then, if a conversion with style E would have an exponent of X: If P > X ≥ −4, the conversion is with style f and precision P − (X + 1). Otherwise, the conversion is with style e and precision P − 1.
G	Like the g specifier but uses E and f.
o	The argument is treated as an integer and presented as an octal number.
s	The argument is treated and presented as a string.
u	The argument is treated as an integer and presented as an unsigned decimal number.
x	The argument is treated as an integer and presented as a hexadecimal number (with lowercase letters).
X	The argument is treated as an integer and presented as a hexadecimal number (with uppercase letters).

Warning: The c type specifier ignores padding and width

Warning: Attempting to use a combination of the string and width specifiers with character sets that require more than one byte per character may result in unexpected results

Variables will be co-erced to a suitable type for the specifier:

Type	Specifiers
string	s
integer	d, u, c, o, x, X, b
double	g, G, e, E, f, F

<?

$format = '%s';
$values = 'Hello';

printf($format, $values);

?>

Hello

2

<?

$format = '%1$s %2$s';
$values1 = 'Hello';
$values2 = 'World!';

printf($format, $values1, $values2);

?>

Hello World!

3

<?

$values = 'justification';

printf("[%-20s]\n", $values);
printf("[%20s]\n", $values);

?>

[justification       ]
[       justification]

4

<?

$values1 = -123456789;
$values2 = 123456789;

printf("%d\n", $values1);
printf("%d\n", $values2);
printf("%+d\n", $values1);
printf("%+d\n", $values2);
printf("%u\n", $values1);
printf("%u\n", $values2);

?>

-123456789
123456789
-123456789
+123456789
18446744073586094827
123456789

5

<?

$values = 'padding';

printf("[%20s]\n", $values);
printf("[%020s]\n", $values);
printf("[%'.20s]\n", $values);
printf("[%'p20s]\n", $values);

?>

[             padding]
[0000000000000padding]
[.............padding]
[ppppppppppppppadding]

6

<?

$values = 'width';

printf("[%10s]\n", $values);
printf("[%20s]\n", $values);
printf("[%30s]\n", $values);
printf("[%40s]\n", $values);

?>

[     width]
[               width]
[                         width]
[                                   width]

7

<?

$values = 0.123456789;

printf("%.2e\n", $values);
printf("%.4e\n", $values);
printf("%e\n", $values);
printf("%.8e\n", $values);
printf("%.2E\n", $values);
printf("%.4E\n", $values);
printf("%E\n", $values);
printf("%.8E\n", $values);
printf("%.2f\n", $values);
printf("%.4f\n", $values);
printf("%f\n", $values);
printf("%.8f\n", $values);
printf("%.2F\n", $values);
printf("%.4F\n", $values);
printf("%F\n", $values);
printf("%.8F\n", $values);

?>

1.23e-1
1.2346e-1
1.234568e-1
1.23456789e-1
1.23E-1
1.2346E-1
1.234568E-1
1.23456789E-1
0.12
0.1235
0.123457
0.12345679
0.12
0.1235
0.123457
0.12345679

8

<?

$values = 123456789;

printf("%.2g\n", $values);
printf("%.4g\n", $values);
printf("%g\n", $values);
printf("%.8g\n", $values);
printf("%.2G\n", $values);
printf("%.4G\n", $values);
printf("%G\n", $values);
printf("%.8G\n", $values);

?>

1.2e+8
1.235e+8
1.23457e+8
1.2345679e+8
1.2E+8
1.235E+8
1.23457E+8
1.2345679E+8

9

<?

$values = 'precision';

printf("%.3s\n", $values);
printf("%.4s\n", $values);
printf("%.5s\n", $values);
printf("%.6s\n", $values);

?>

pre
prec
preci
precis

10

<?

$values = 123456789;

printf("%%b = %b\n", $values);
printf("%%d = %d\n", $values);
printf("%%e = %e\n", $values);
printf("%%E = %E\n", $values);
printf("%%f = %f\n", $values);
printf("%%F = %F\n", $values);
printf("%%g = %g\n", $values);
printf("%%G = %G\n", $values);
printf("%%o = %o\n", $values);
printf("%%s = %s\n", $values);
printf("%%u = %u\n", $values);
printf("%%x = %x\n", $values);
printf("%%X = %X\n", $values);

?>

%b = 111010110111100110100010101
%d = 123456789
%e = 1.234568e+8
%E = 1.234568E+8
%f = 123456789.000000
%F = 123456789.000000
%g = 1.23457e+8
%G = 1.23457E+8
%o = 726746425
%s = 123456789
%u = 123456789
%x = 75bcd15
%X = 75BCD15

11

<?

$values = 65;

printf("%%c = %c\n", $values);

?>

%c = A

12 · return

<?

$format = '%s';
$values = 'Hello';

$return = printf($format, $values);

echo PHP_EOL . $return;

?>

Hello
5