PHPWales 2020 - June 3rd to June 4th

SplFileObject::fscanf

(PHP 5 >= 5.1.0, PHP 7)

SplFileObject::fscanfフォーマットに従ってファイルからの入力をパースする

説明

public SplFileObject::fscanf ( string $format [, mixed &$... ] ) : mixed

ファイルから 1 行読み込み、sprintf() のドキュメントで説明される規定の format に従って解釈されます。

format 文字列のホワイトスペースはファイルからの行のホワイトスペースとマッチします。このことが意味するのはフォーマット文字列のタブ (\t) でさえも入力ストリームの 1 つのスペース文字とマッチしてしまうということです。

パラメータ

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: %[flags][width][.precision]specifier.

Flags
Flag 説明
- 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).

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.

注意: If the period is specified without an explicit value for precision, 0 is assumed.

注意: Attempting to use a position specifier greater than PHP_INT_MAX will generate warnings.

Specifiers
Specifier 説明
% 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). The precision specifier stands for the number of digits after the decimal point since PHP 5.2.1. In earlier versions, it was taken as number of significant digits (one less).
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). Available as of PHP 5.0.3.
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).

警告

The c type specifier ignores padding and width

警告

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
integer d, u, c, o, x, X, b
double g, G, e, E, f, F

...

オプションの割り当て値。

返り値

このメソッドに渡される引数がひとつしかない場合、処理される値は配列として返されます。そうでなければ、オプションパラメータが渡される場合、メソッドは割り当て値の個数を返します。オプションパラメータは参照渡しでなければなりません。

例1 SplFileObject::fscanf() の例

<?php
$file 
= new SplFileObject("misc.txt");
while (
$userinfo $file->fscanf("%s %s %s")) {
    list (
$name$profession$countrycode) = $userinfo;
    
// $name $profession $countrycode で何かを行う
}
?>

users.txt の内容

javier   argonaut    pe
hiroshi  sculptor    jp
robert   slacker     us
luigi    florist     it

参考

  • fscanf() - フォーマットに基づきファイルからの入力を処理する
  • sscanf() - フォーマット文字列に基づき入力を処理する
  • printf() - フォーマット済みの文字列を出力する
  • sprintf() - フォーマットされた文字列を返す

add a note add a note

User Contributed Notes

There are no user contributed notes for this page.
To Top