(PHP 5 >= 5.1.0, PHP 7, PHP 8)
SplFileObject::fscanf — Parses input from file according to a format
Reads a line from the file and interprets it according to the specified format, which is
described in the documentation for sprintf().
Any whitespace in the format string matches any whitespace in the line from the file.
This means that even a tab \t in the format string can match a single space character in the input stream.
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.
An integer followed by a dollar sign $,
to specify which number argument to treat in the conversion.
| Flag | 说明 |
|---|---|
- |
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). |
An integer that says how many characters (minimum) this conversion should result in.
A period . followed by an integer
who's meaning depends on the specifier:
e, E,
f and F
specifiers: this is the number of digits to be printed
after the decimal point (by default, this is 6).
g, G,
h and H
specifiers: this is the maximum number of significant
digits to be printed.
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_MAXwill generate warnings.
| Specifier | 说明 |
|---|---|
% |
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.
|
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. |
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). |
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 | Specifiers |
|---|---|
| string | s |
| int |
d,
u,
c,
o,
x,
X,
b
|
| float |
e,
E,
f,
F,
g,
G,
h,
H
|
varsThe optional assigned values.
If only one parameter is passed to this method, 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.
Example #1 SplFileObject::fscanf() example
<?php
$file = new SplFileObject("misc.txt");
while ($userinfo = $file->fscanf("%s %s %s")) {
list ($name, $profession, $countrycode) = $userinfo;
// Do something with $name $profession $countrycode
}
?>
Contents of users.txt
javier argonaut pe hiroshi sculptor jp robert slacker us luigi florist it