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printf
Output a formatted string
Description
int printf(string $format, mixed ...$values)
Produces output according to format.
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).
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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 uses
E and f.
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h |
Like the g specifier but uses F.
Available as of PHP 8.0.0.
|
H |
Like the g specifier but uses
E and F. Available as of PHP 8.0.0.
|
o |
The argument is treated as an integer and presented
as an octal number.
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s |
The argument is treated and presented as a string.
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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).
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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 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.
Examples
Example #1 printf: various examples
<?php
$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
<?php
$s = 'monkey';
$t = 'many monkeys';
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
- sprintf
- fprintf
- vprintf
- vsprintf
- vfprintf
- sscanf
- fscanf
- number_format
- date
- flush
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