fscanf

(PHP 4 >= 4.0.1, PHP 5, PHP 7)

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

用户评论:

[#1] hdh265 at 163 dot com [2015-04-13 05:19:56]

The use of PHP code in the ACM submission
Here is a sample solution for problem 1001 using PHP:
<?php
while (fscanf(STDIN, "%d%d", $a, $b) == 2) {
print ($a + $b) . "\n";
}

[#2] nico at nicoswd dot com [2013-08-28 21:25:01]

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")) { } ?>

[#3] arentzen at religion dot dk [2007-09-30 02:56:04]

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()
<?php $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()

[#4] Bertrand dot Lecun at prism dot uvsq dot Fr [2007-05-30 00:48:31]

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.

[#5] loco.xxx at gmail dot com [2006-07-24 00:46:33]

to include all type of visible chars you should try:

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

[#6] worldwideroach at hotmail dot com [2005-07-14 09:33:15]

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;
}

[#7] robert at NOSPAM dot NOSPAM [2002-10-24 16:08:36]

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.

[#8] eugene at pro-access dot com [2002-03-16 00:39:28]

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.

[#9] james at zephyr-works dot com [2001-07-08 00:29:41]

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.

[#10] yasuo_ohgaki at hotmail dot com [2001-03-12 23:59:52]

For C/C++ programmers.

fscanf() does not work like C/C++, because PHP's fscanf() move file pointer the next line implicitly.