SunshinePHP Developer Conference 2015

fscanf

(PHP 4 >= 4.0.1, PHP 5)

fscanf从文件中格式化输入

说明

mixed fscanf ( resource $handle , string $format [, mixed &$... ] )

fscanf() 函数和 sscanf() 相似,但是它从与 handle 关联的文件中接受输入并根据指定的 format(定义于 sprintf() 的文档中)来解释输入。

格式字符串中的任何空白会与输入流中的任何空白匹配。这意味着甚至格式字符串中的制表符 \t 也会与输入流中的一个空格字符匹配。

每次调用 fscanf() 都会从文件中读取一行。

参数

handle

文件系统指针,是典型地由 fopen() 创建的 resource(资源)。

format

参数格式是 sprintf() 文档中所描述的格式。

...

The optional assigned values.

返回值

如果只给此函数传递了两个参数,解析后的值会被作为数组返回。否则,如果提供了可选参数,此函数将返回被赋值的数目。 可选参数必须用引用传递。

更新日志

版本 说明
4.3.0 在 PHP 4.3.0 之前,从文件中读入的最大字符数是 512(或者第一个 \n,看先碰到哪种情况)。从 PHP 4.3.0 起可以读取任意长的行。

范例

Example #1 fscanf() 例子

<?php
$handle 
fopen("users.txt""r");
while (
$userinfo fscanf($handle"%s\t%s\t%s\n")) {
    list (
$name$profession$countrycode) = $userinfo;
    
//... do something with the values
}
fclose($handle);
?>

Example #2 users.txt 的内容

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

参见

  • fread() - 读取文件(可安全用于二进制文件)
  • fgets() - 从文件指针中读取一行
  • fgetss() - 从文件指针中读取一行并过滤掉 HTML 标记
  • sscanf() - 根据指定格式解析输入的字符
  • printf() - 输出格式化字符串
  • sprintf() - Return a formatted string

add a note add a note

User Contributed Notes 9 notes

up
3
yasuo_ohgaki at hotmail dot com
13 years ago
For C/C++ programmers.

fscanf() does not work like C/C++, because PHP's fscanf() move file pointer the next line implicitly.
up
1
arentzen at religion dot dk
7 years ago
If you want fscanf()to scan one variable in a large number of lines,  e.g an Ipadress in a line with more variables, then use fscanf with explode()
<?
$filename = "somefile.txt";
$fp = fopen($filename, "r") or die ("Error opening file! \n");
$u = explode(" ",$line); // $u is the variable eg. an IPadress
while ($line = fscanf($fp,"%s",$u)) {
if(preg_match("/^$u/",$_SERVER['REMOTE_ADDR'])) {$badipadresss++;} // do something and continue scan
}
?>
Besides, fscanf()is much faster than fgets()
up
1
worldwideroach at hotmail dot com
9 years ago
Yet another function to read a file and return a record/string by a delimiter.  It is very much like fgets() with the delimiter being an additional parameter.  Works great across multiple lines.

function fgetd(&$rFile, $sDelim, $iBuffer=1024) {
    $sRecord = '';
    while(!feof($rFile)) {
        $iPos = strpos($sRecord, $sDelim);
        if ($iPos === false) {
            $sRecord .= fread($rFile, $iBuffer);
        } else {
            fseek($rFile, 0-strlen($sRecord)+$iPos+strlen($sDelim), SEEK_CUR);
            return substr($sRecord, 0, $iPos);
        }
    }
    return false;
}
up
2
nico at nicoswd dot com
1 year ago
If you want to parse a cron file, you may use this pattern:

<?php

while ($cron = fscanf($fp, "%s %s %s %s %s %[^\n]s"))
{

}

?>
up
2
eugene at pro-access dot com
12 years ago
If you want to read text files in csv format or the like(no matter what character the fields are separated with), you should use fgetcsv() instead. When a text for a field is blank, fscanf() may skip it and fill it with the next text, whereas fgetcsv() correctly regards it as a blank field.
up
0
Bertrand dot Lecun at prism dot uvsq dot Fr
7 years ago
It would be great to precise in the fscanf documentation
that one call to the function, reads a complete line.
and not just the number of values defined in the format.

If a text file contains 2 lines each containing 4 integer values,
reading the file with 8 fscanf($fd,"%d",$v) doesnt run !
You have to make 2
fscanf($fd,"%d %d %d %d",$v1,$v2,$v3,$v4);

Then 1 fscanf per line.
up
0
robert at NOSPAM dot NOSPAM
11 years ago
actually, instead of trying to think of every character that might be in your file, excluding the delimiter would be much easier.

for example, if your delimiter was a comma use:

%[^,]

instead of:

%[a-zA-Z0-9.| ... ]

Just make sure to use %[^,\n] on your last entry so you don't include the newline.
up
0
james at zephyr-works dot com
13 years ago
fscanf works a little retardedly I've found. Instead of using just a plain %s you probably will need to use sets instead. Because it works so screwy compared to C/C++, fscanf does not have the ability to scan ahead in a string and pattern match correctly, so a seemingly perfect function call like:

fscanf($fh, "%s::%s");

With a file like:

user::password

Will not work. When fscanf looks for a string, it will look and stop at nothing except for a whitespace so :: and everything except whitespace is considered part of that string, however you can make it a little smarter by:

fscanf($fh, "%[a-zA-Z0-9,. ]::%[a-zA-Z0-9,. ]" $var1, $var2);

Which tells it that it can only accept a through z A through Z 0 through 9 a comma a period and a whitespace as input to the string, everything else cause it to stop taking in as input and continue parsing the line. This is very useful if you want to get a sentence into the string and you're not sure of exactly how many words to add, etc.
up
-1
loco.xxx at gmail dot com
8 years ago
to include all type of visible chars you should try:

<?php fscanf($file_handler,"%[ -~]"); ?>
To Top