printf
(PHP 4, PHP 5, PHP 7, PHP 8)
printf — Output a formatted string
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.Pads the result with spaces. This is the default. 0Only left-pads numbers with zeros. With sspecifiers 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,fandFspecifiers: this is the number of digits to be printed after the decimal point (by default, this is 6). -
For
g,G,handHspecifiers: this is the maximum number of significant digits to be printed. -
For
sspecifier: 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_MAXwill generate warnings.Specifiers Specifier Description %A literal percent character. No argument is required. bThe argument is treated as an integer and presented as a binary number. cThe argument is treated as an integer and presented as the character with that ASCII. dThe argument is treated as an integer and presented as a (signed) decimal number. eThe argument is treated as scientific notation (e.g. 1.2e+2). ELike the especifier but uses uppercase letter (e.g. 1.2E+2).fThe argument is treated as a float and presented as a floating-point number (locale aware). FThe argument is treated as a float and presented as a floating-point number (non-locale aware). gGeneral 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.
GLike the gspecifier but usesEandf.hLike the gspecifier but usesF. Available as of PHP 8.0.0.HLike the gspecifier but usesEandF. Available as of PHP 8.0.0.oThe argument is treated as an integer and presented as an octal number. sThe argument is treated and presented as a string. uThe argument is treated as an integer and presented as an unsigned decimal number. xThe argument is treated as an integer and presented as a hexadecimal number (with lowercase letters). XThe argument is treated as an integer and presented as a hexadecimal number (with uppercase letters). WarningThe
ctype specifier ignores padding and widthWarningAttempting 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 sint d,u,c,o,x,X,bfloat e,E,f,F,g,G,h,H -
For
-
values -
Return Values
Returns the length of the outputted string.
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("[%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] [ 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
