PHP: Hypertext Preprocessor (original) (raw)

vprintf

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

vprintf — Output a formatted string

Description

Operates as printf() but accepts an array of arguments, rather than a variable number of arguments.

Parameters

format

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

Either an integer that says how many characters (minimum) this conversion should result in, or *. If * is used, then the width is supplied as an additional integer value preceding the one formatted by the specifier.

Precision

A period . optionally followed by either an integer or *, whose 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, G,h and H 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. If * is used, the precision is supplied as an additional integer value preceding the one formatted by the specifier.

Specifiers

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).
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 usesE and f.
h	Like the g specifier but uses F. Available as of PHP 8.0.0.
H	Like the g specifier but usesE and F. Available as of PHP 8.0.0.
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 Handling

Type	Specifiers
string	s
int	d,u,c,o,x,X,b
float	e,E,f,F,g,G,h,H

values

Return Values

Returns the length of the outputted string.

Errors/Exceptions

As of PHP 8.0.0, a ValueError is thrown if the number of arguments is zero. Prior to PHP 8.0.0, a [E_WARNING](errorfunc.constants.php#constant.e-warning) was emitted instead.

As of PHP 8.0.0, a ValueError is thrown if [width] is less than zero or bigger than [PHP_INT_MAX](reserved.constants.php#constant.php-int-max). Prior to PHP 8.0.0, a [E_WARNING](errorfunc.constants.php#constant.e-warning) was emitted instead.

As of PHP 8.0.0, a ValueError is thrown if [precision] is less than zero or bigger than [PHP_INT_MAX](reserved.constants.php#constant.php-int-max). Prior to PHP 8.0.0, a [E_WARNING](errorfunc.constants.php#constant.e-warning) was emitted instead.

As of PHP 8.0.0, a ValueError is thrown when less arguments are given than required. Prior to PHP 8.0.0, [false](reserved.constants.php#constant.false) was returned and a [E_WARNING](errorfunc.constants.php#constant.e-warning) emitted instead.

Changelog

Version	Description
8.0.0	This function no longer returns false on failure.
8.0.0	Throw a ValueError if the number of arguments is zero; previously this function emitted a E_WARNING instead.
8.0.0	Throw a ValueError if [width] is less than zero or bigger than PHP_INT_MAX; previously this function emitted a E_WARNING instead.
8.0.0	Throw a ValueError if [precision] is less than zero or bigger than PHP_INT_MAX; previously this function emitted a E_WARNING instead.
8.0.0	Throw a ValueError when less arguments are given than required; previously this function emitted a E_WARNING instead.

Examples

Example #1 vprintf(): zero-padded integers

<?php vprintf("%04d-%02d-%02d", explode('-', '1988-8-1')); ?>

The above example will output:

Found A Problem?

steve at stevelockwood dot net ¶

10 years ago

If, instead of an array, you pass an object PHP will automatically cast the object as an array so you can use it directly in vprintf. <?php $object = new stdClass(); $object->Property1 = 'Value 1'; $object->Property2 = 'Value 2'; vprintf('%-20s %-20s', $object);/* will output Value 1 Value 2 */ ?>

phpcoder at gmail dot com ¶

5 years ago

Using the ... operator, vprintf($format, <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>a</mi><mi>r</mi><mi>r</mi><mi>a</mi><mi>y</mi><mo stretchy="false">)</mo><mi>i</mi><mi>s</mi><mi>b</mi><mi>a</mi><mi>s</mi><mi>i</mi><mi>c</mi><mi>a</mi><mi>l</mi><mi>l</mi><mi>y</mi><mi>j</mi><mi>u</mi><mi>s</mi><mi>t</mi><mi>p</mi><mi>r</mi><mi>i</mi><mi>n</mi><mi>t</mi><mi>f</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">array) is basically just printf(</annotation></semantics></math>array)isbasicallyjustprintf(format, ...$array).

taken from "Php Phrasebook" ¶

16 years ago

` Version %s; Major:%d.',$matches); ?>

output:
Array ( [0] => PHP 5.2.5 [1] => 5.2.5 [2] => 5 )
Match: PHP 5.2.5 Version 5.2.5; Major:5.

For preg_match:

If matches is provided, then it is filled with the results of search. matches[0]willcontainthetextthatmatchedthefullpattern,matches[0] will contain the text that matched the full pattern, matches[0]willcontainthetextthatmatchedthefullpattern,matches[1] will have the text that matched the first captured parenthesized subpattern, and so on.

tehjosh at gamingg dot net ¶

17 years ago

`To toolofthesystem at gmail dot com:

You don't need to use output buffering with vprintf() because you can use vsprintf(), which has the same functionality as vprintf(), except that it returns the resulting string instead of outputting it.

caleb at tekhawk dot com ¶

18 years ago

`i know that you can use %1$s or %3$s to select the first or third string but how can you or can you use array names to select it

something like %'user'$s ′email′'email'′email′s

i tend to add things to my databases over time and this could save loads of recoding

Chris ¶

12 years ago

`Another way to display arrays is use an array_walk(). This can be useful inline echo/print where a foreach wouldn't work, e.g.

"; } ), "must be corrected."; ?>

badcop666 at hotmail dot com ¶

17 years ago

`For blocks of text, sprintf() is slow according to my tests.

Also, having the mapping between place-holders and the list of actual variables or datastructures often makes this code difficult to read. But the printf() family are widely supported and have a huge range of nice features. Performance is a cold mistress though!

From an ease-of-reading and maintenance, debugging point of view, I much prefer HEREDOC and "...{$variable}..." methods.

For a block of HTML markup with place holders, the fastest by far was:-

markup etcmore markup My tests comprised 20 runs of a loop of 1 million iterations with output buffering, ditching the buffer on each loop.

The timings ranged from average 2.1msec/million repetitions for the method up to 7.6msec/million using printf().

I'll try some benchmarking tools too, since I just wrote this myself and it could be introducing bias, but they've run on dev servers with low load.

Hopefully interesting.

toolofthesystem at gmail dot com ¶