Print with php code

printf

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
  • 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.

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:

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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.

The c type specifier ignores padding and width

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

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 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 . Prior to PHP 8.0.0, a 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 . Prior to PHP 8.0.0, a E_WARNING was emitted instead.

As of PHP 8.0.0, a ArgumentCountError is thrown when less arguments are given than required. Prior to PHP 8.0.0, false was returned and a 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 ArgumentCountError when less arguments are given than required; previously this function emitted a E_WARNING instead.

Examples

Example #1 printf() : various examples

$n = 43951789 ;
$u = — 43951789 ;
$c = 65 ; // ASCII 65 is ‘A’

// notice the double %%, this prints a literal ‘%’ character
printf ( «%%b = ‘%b’\n» , $n ); // binary representation
printf ( «%%c = ‘%c’\n» , $c ); // print the ascii character, same as chr() function
printf ( «%%d = ‘%d’\n» , $n ); // standard integer representation
printf ( «%%e = ‘%e’\n» , $n ); // scientific notation
printf ( «%%u = ‘%u’\n» , $n ); // unsigned integer representation of a positive integer
printf ( «%%u = ‘%u’\n» , $u ); // unsigned integer representation of a negative integer
printf ( «%%f = ‘%f’\n» , $n ); // floating point representation
printf ( «%%o = ‘%o’\n» , $n ); // octal representation
printf ( «%%s = ‘%s’\n» , $n ); // string representation
printf ( «%%x = ‘%x’\n» , $n ); // hexadecimal representation (lower-case)
printf ( «%%X = ‘%X’\n» , $n ); // hexadecimal representation (upper-case)

printf ( «%%+d = ‘%+d’\n» , $n ); // sign specifier on a positive integer
printf ( «%%+d = ‘%+d’\n» , $u ); // sign specifier on a negative integer
?>

The above example will output:

%b = '10100111101010011010101101' %c = 'A' %d = '43951789' %e = '4.39518e+7' %u = '43951789' %u = '4251015507' %f = '43951789.000000' %o = '247523255' %s = '43951789' %x = '29ea6ad' %X = '29EA6AD' %+d = '+43951789' %+d = '-43951789'

Example #2 printf() : string specifiers

printf ( «[%s]\n» , $s ); // standard string output
printf ( «[%10s]\n» , $s ); // right-justification with spaces
printf ( «[%-10s]\n» , $s ); // left-justification with spaces
printf ( «[%010s]\n» , $s ); // zero-padding works on strings too
printf ( «[%’#10s]\n» , $s ); // use the custom padding character ‘#’
printf ( «[%’#*s]\n» , 10 , $s ); // Provide the padding width as an additional argument
printf ( «[%10.9s]\n» , $t ); // right-justification but with a cutoff of 8 characters
printf ( «[%-10.9s]\n» , $t ); // left-justification but with a cutoff of 8 characters
?>

The above example will output:

[monkey] [ monkey] [monkey ] [0000monkey] [####monkey] [####monkey] [ many monk] [many monk ]

See Also

  • print — Output a string
  • sprintf() — Return a formatted string
  • fprintf() — Write a formatted string to a stream
  • vprintf() — Output a formatted string
  • vsprintf() — Return a formatted string
  • vfprintf() — Write a formatted string to a stream
  • sscanf() — Parses input from a string according to a format
  • fscanf() — Parses input from a file according to a format
  • number_format() — Format a number with grouped thousands
  • date() — Format a Unix timestamp
  • flush() — Flush system output buffer

User Contributed Notes 17 notes

Be careful:
printf («(9.95 * 100) = %d \n», (9.95 * 100));

First %d converts a float to an int by truncation.

Second floats are notorious for tiny little rounding errors.

To provide a more user-friendly interface, you can use colors when printing text in the terminal.

p(‘Ordinary text.’);
p(‘Warning: Check this out. ‘, ‘info’);
p(‘Ops! Something went wrong.’, ‘error’);
p(‘Yeah. done!’, ‘success’);

function p($text, $style = », $newLine = true)

$styles = array(
‘success’ => «\033[0;32m%s\033[0m»,
‘error’ => «\033[31;31m%s\033[0m»,
‘info’ => «\033[33;33m%s\033[0m»,

‘Black’ => «\033[0;30m%s\033[0m»,
‘Red’ => «\033[0;31m%s\033[0m»,
‘Green’ => «\033[0;32m%s\033[0m»,
‘Yellow’ => «\033[0;33m%s\033[0m»,
‘Blue’ => «\033[0;34m%s\033[0m»,
‘Purple’ => «\033[0;35m%s\033[0m»,
‘Cyan’ => «\033[0;36m%s\033[0m»,
‘Gray’ => «\033[0;37m%s\033[0m»,
‘Graphite’ => «\033[1;30m%s\033[0m»,

‘Bold Red’ => «\033[1;31m%s\033[0m»,
‘Bold Green’ => «\033[1;32m%s\033[0m»,
‘Bold Yellow’ => «\033[1;33m%s\033[0m»,
‘Bold Blue’ => «\033[1;34m%s\033[0m»,
‘Bold Purple’ => «\033[1;35m%s\033[0m»,
‘Bold Cyan’ => «\033[1;36m%s\033[0m»,
‘Bold White’ => «\033[1;37m%s\033[0m»,

‘Bg Black’ => «\033[40;1;37m%s\033[0m»,
‘Bg Red’ => «\033[41;1;37m%s\033[0m»,
‘Bg Green’ => «\033[42;1;37m%s\033[0m»,
‘Bg Yellow’ => «\033[43;1;37m%s\033[0m»,
‘Bg Blue’ => «\033[44;1;37m%s\033[0m»,
‘Bg Purple’ => «\033[45;1;37m%s\033[0m»,
‘Bg Cyan’ => «\033[46;1;37m%s\033[0m»,
‘Bg Gray’ => «\033[47;1;37m%s\033[0m»,

‘Underscore’ => «\033[4;37m%s\033[0m»,
‘Inverted’ => «\033[7;37m%s\033[0m»,
‘Blink’ => «\033[5;37m%s\033[0m»,
);

if (isset($styles[$style])) $format = $styles[$style];
>

if ($newLine) $format .= PHP_EOL;
>

[Editor’s Note: Or just use vprintf. ]

function printf_array ( $format , $arr )
<
return call_user_func_array ( ‘printf’ , array_merge ((array) $format , $arr ));
>
?>

Use it the following way:
$goodevil = array( ‘good’ , ‘evil’ );
printf_array ( ‘There is a difference between %s and %s’ , $goodevil );
?>
and it will print:
There is a difference between good and evil

You can use this function to format the decimal places in a number:

instead of writing a function to round off a float (let’s call it ‘x’) accurately, it’s much easier to add a small number to x and then truncate it.
For example: if you want to round off to the nearest integer, just add 0.5 to x and then truncate it. if x=12.6, then it would calculate 13.1, and truncate it to 13. If x=14.4, it would calculate 14.9 and truncate it to 14.

Be careful when relying on typecasting with printf(). For example,

Be sure that the output channel is available to write on before executing printf()! Some functions in classes available from various sources (in my case, DB_Sql::query() in PHPLIB) assume that printing will work, even after the default output stream has been closed.

For me the issue was most notable in PHP4 session management when I was creating my own sess_write() handler. Since I was unable to find any function that checks for the output stream that printf() uses, I just had to drop the crazy use of the printf(). (does some function already exist to check for the presence of an output stream?)

To format a dollar value as in $123.00 that may otherwise look like $123 use this

print (‘$’); // the dollar sign in front of our answer
printf (‘%.2f’,$price);

If anyone is looking for writing a quine using printf(),
this is my example:

‘ ; printf ( $f , 39 , $f , 39 ); ?>

This also helps those who are new to printf() see one way of using the ‘mixed args’ part, rather than just a single argument as in most examples I’ve seen.

If your missing features such as «-«*100 to print a single character multiple times you can use the slightly longer and less readable PHP equivalent printf(«%’-100s»,»»); and sprint(«%’-100s»,»»).

be careful with integers, they cant hold large values.

printf(«%d»,10023123553.45634663);
will print out: 1433188961
and
printf(«%.0f»,10023123553.45634663);
will print out: 10023123553

A format specification, which consists of optional and required fields, has the following form:

%[flags] [width] [.precision] []type

Each field of the format specification is a single character or a number signifying a particular format option. The simplest format specification contains only the percent sign and a type character (for example, %s). If a percent sign is followed by a character that has no meaning as a format field, the character is copied to stdout. For example, to print a percent-sign character, use %%.

The optional fields, which appear before the type character, control other aspects of the formatting, as follows:

type
Required character that determines whether the associated argument is interpreted as a character, a string, or a number (see the printf Type Field Characters table.
flags
Optional character or characters that control justification of output and printing of signs, blanks, decimal points, and octal and hexadecimal prefixes (see the Flag Characters table). More than one flag can appear in a format specification.
width
Optional number that specifies the minimum number of characters output (see printf Width Specification).
precision
Optional number that specifies the maximum number of characters printed for all or part of the output field, or the minimum number of digits printed for integer values (see the How Precision Values Affect Type table).
h | l | I64 | L
Optional prefixes to type-that specify the size of argument (see the Size Prefixes for printf and wprintf Format-Type Specifiers table).

I don’t know if this is useful to anyone, but here goes! Example for using the printf function to output an object.

class person
var $name = «»;
function name($newname = NULL)
if(! is_null($newname))
$this->name=$newname;
>
return $this->name;
>
var $surname = «»;
function surname($newsurname = NULL)
if(! is_null($newsurname))
$this->surname=$newsurname;
>
return $this->surname;
>
var $age = «»;
function age($newage = NULL)
if(! is_null($newage))
$this->age=$newage;
>
return $this->age;
>
>

$bob = new person;
$bob->name(‘Bob’);
$bob->surname(‘Builder’);
$bob->age(’50’);

printf(«Hi %s, your surname is %s and you are %s years old», $bob->name, $bob->surname, $bob->age);

Hi Bob, your surname is Builder and you are 50 years old

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