fscanf()
(PHP 4 >= 4.0.1, PHP 5, PHP 7)
从文件中格式化输入
说明
fscanf(resource $handle,string $format[,mixed&$...
]): 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 #1fscanf()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); ?>
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
For C/C++ programmers. fscanf() does not work like C/C++, because PHP's fscanf() move file pointer the next line implicitly.
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,$v4); Then 1 fscanf per line.
If you want to read text files in csv format or the like(no matter what character the fields are separated with), you should use fgetcsv() instead. When a text for a field is blank, fscanf() may skip it and fill it with the next text, whereas fgetcsv() correctly regards it as a blank field.
If you want to parse a cron file, you may use this pattern: <?php while ($cron = fscanf($fp, "%s %s %s %s %s %[^\n]s")) { } ?>
Yet another function to read a file and return a record/string by a delimiter. It is very much like fgets() with the delimiter being an additional parameter. Works great across multiple lines. function fgetd(&$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, $iPos); } } return false; }
actually, instead of trying to think of every character that might be in your file, excluding the delimiter would be much easier. for example, if your delimiter was a comma use: %[^,] instead of: %[a-zA-Z0-9.| ... ] Just make sure to use %[^,\n] on your last entry so you don't include the newline.
to include all type of visible chars you should try: <?php fscanf($file_handler,"%[ -~]"); ?>
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.
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()
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"; }