fscanf

Description
Syntax
Examples
Links

Description

The fscanf of Filesystem for PHP parses input from a file according to a format.

Syntax

fscanf(
    resource $stream,
    string $format,
    mixed &...$vars
): array|int|false|null

Parameters

stream

A file system pointer resource that is typically created using fopen().

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.
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

vars

The optional assigned values.

Return

If only two parameters were passed to this function, the values parsed will be returned as an array. Otherwise, if optional parameters are passed, the function will return the number of assigned values. The optional parameters must be passed by reference.

If there are more substrings expected in the format than there are available within string, null will be returned. On other errors, false will be returned.

Examples

1 · stream format

<?

$filename = $_SERVER['DOCUMENT_ROOT'] . '/assets/txt/2.txt';
$mode = 'r';

$stream = fopen($filename, $mode);

    $format = "%d\t%s\n";

    while($return = fscanf($stream, $format))
    {
        list($number, $name) = $return;
        echo "$number\t$name\n";
    }

fclose($stream);

?>

1    john
2    paul
3    george
4    ringo