php教程

file

(PHP 4, PHP 5, PHP 7)

file — 把整个文件读入一个数组中

说明

file ( string $filename [, int $flags = 0 [, resource $context ]] ) : array

把整个文件读入一个数组中。

Note:

你可以通过 file_get_contents() 以字符串形式获取文件的内容。

参数

filename

文件的路径。

Tip

如已启用fopen 包装器，在此函数中， URL 可作为文件名。关于如何指定文件名详见 fopen()。各种 wapper 的不同功能请参见 支持的协议和封装协议，注意其用法及其可提供的预定义变量。

flags

可选参数 flags 可以是以下一个或多个常量：

FILE_USE_INCLUDE_PATH
在 include_path 中查找文件。
FILE_IGNORE_NEW_LINES
在数组每个元素的末尾不要添加换行符
FILE_SKIP_EMPTY_LINES
跳过空行

context

A context resource created with the stream_context_create() function.

Note: 在 PHP 5.0.0 中增加了对上下文（Context）的支持。有关上下文（Context）的说明参见 Streams。

返回值

Returns the file in an array. Each element of the array corresponds to a line in the file, with the newline still attached. Upon failure, file() returns FALSE.

Note:

Each line in the resulting array will include the line ending, unless FILE_IGNORE_NEW_LINES is used, so you still need to use rtrim() if you do not want the line ending present.

Note: 在读取在 Macintosh 电脑中或由其创建的文件时， 如果 PHP 不能正确的识别行结束符，启用运行时配置可选项 auto_detect_line_endings 也许可以解决此问题。

更新日志

版本 说明
5.0.0 增加了参数 context
5.0.0 Prior to PHP 5.0.0 the flags parameter only covered include_path and was enabled with 1
4.3.0 file() 开始是二进制安全的

范例

Example #1 file() 例子

<?php
// 将一个文件读入数组。本例中通过 HTTP 从 URL 中取得 HTML 源文件。

$lines = file('http://www.example.com/');

// 在数组中循环，显示 HTML 的源文件并加上行号。

foreach ($lines as $line_num => $line) {
    echo "Line #<b>{$line_num}</b> : " . htmlspecialchars($line) . "<br />\n";
}

// 另一个例子将 web 页面读入字符串。参见 file_get_contents()。

$html = implode('', file('http://www.example.com/'));

// 从 PHP 5 开始可以使用可选标记参数
$trimmed = file('somefile.txt', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
?>

注释

Warning

使用 SSL 时，Microsoft IIS 会违反协议不发送close_notify标记就关闭连接。PHP 会在到达数据尾端时报告"SSL: Fatal Protocol Error"。 要解决此问题，error_reporting 应设定为降低级别至不包含警告。 PHP 4.3.7 及更高版本可以在使用 https:// 包装器打开流时检测出有问题的 IIS 服务器软件 并抑制警告。在使用 fsockopen() 创建 ssl:// 套接字时, 开发者需检测并抑制此警告。

参见

User Contributed Notes

sheldon at hyperlinked dot com 29-May-2019 10:25
As of PHP 5.6 the file(), file_get_contents(), and fopen() functions will return false if you are referencing a source URL that doesn't have a valid SSL certificate. Presumably, you will run into this a lot in your development environments this will drive you crazy.

You will need to create a stream context and provide it as an argument to the various file operations to tell it to ignore invalid SSL credentials.

$args = array("ssl"=>array("verify_peer"=>false,"verify_peer_name"=>false),"http"=>array('timeout' => 60, 'user_agent' => 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.9) Gecko/20071025 Firefox/3.0.0.1'));

$context = stream_context_create($args);
$httpfile = file($url, false, $context);
radler63 at hotmail dot com 04-Oct-2018 04:34
My experience is that the function file does uses the cached content if the file has changed....
lanresmith 01-Jun-2017 01:32
Using if ( file(name.txt) ) might not be enough for testing if the file was successfully opened for reading because the file could be empty in which case the array returned is empty, so test instead with !==. e.g.:

$file_array = file('test.txt'); // an empty file

echo '<pre>';
if ( $file_array ) {
    # code...
    echo "success\n";
} else {
    # code...
    echo "failure\n"; // executed
}

if ( $file_array !== false ) {
    # code...
    echo "success\n"; // executed
} else {
    # code...
    echo "failure\n";
}
echo '</pre>';

result:
failure
success
Martin K. 05-Aug-2014 04:38
If the file you are reading is in CSV format do not use file(), use fgetcsv().  file() will split the file by each newline that it finds, even newlines that appear within a field (i.e. within quotations).
marco dot remy at aol dot com 17-Jun-2014 07:54
Here's my CSV converter
supports Header and trims all fields
Note: Headers must be not empty!

<?php

function csv2array($file, $delim = ';', $encl = '"', $header = false) {
   
    # File does not exist
    if(!file_exists($file))
        return false;
   
    # Read lines of file to array
    $file_lines = file($file, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
   
    # Empty file
    if($file_lines === array())
        return NULL;
   
    # Read headers if you want to
    if($header === true) {
        $line_header = array_shift($file_lines);
        $array_header = array_map('trim', str_getcsv($line_header, $delim, $encl));
    }

    $out = NULL;

    # Now line per line (strings)
    foreach ($file_lines as $line) {
        # Skip empty lines
        if(trim($line) === '')
            continue;
       
        # Convert line to array
        $array_fields = array_map('trim', str_getcsv($line, $delim, $encl));
       
        # If header present, combine header and fields as key => value
        if($header === true)
            $out[] = array_combine ($array_header, $array_fields);
        else
            $out[] = $array_fields;
    }
   
    return $out;
}
?>
Anonymous 25-Dec-2013 04:31
("file()'s problem with UTF-16" is wrong. This is updated.
The former may miss the last line of the string.)

file() seems to have a problem in handling
UTF-16 with or without BOM.

file() is likely to think "\n"=LF (0A) as a line-ending.
So, not only "000A" but also "010A, 020A,...,FE0A, FF0A,..."
are regarded as line-endings.

Moreover, file() causes a serious problem in UTF-16LE.
file() loses first "0A" (the first half of "0A00")!
And the next line begins with "00" (the rest of "0A00").
So lines after the first "0A" are totally different.

To avoid this phenomena,
eg. in case (php_script : UTF-8 , file : UTF-16 with line-ending "\r\n"),

<?php

mb_regex_encoding('UTF-16');    // to help mb_ereg_..() work properly
$str = file_get_contents($file_path);
$to_encoding = 'UTF-16';        // encoding of string
$from_encoding = 'UTF-8';        // encoding of PHP_script
$pattern1 = mb_convert_encoding('[^\r]*\r\n', $to_encoding, $from_encoding);
mb_ereg_search_init($str, $pattern1);
while ($res = mb_ereg_search_regs()) {
    $file[] = $res[0];
}
$pattern2 = mb_convert_encoding('\A.*\r\n(.*)\z', $to_encoding, $from_encoding);
mb_ereg($pattern2, $str, $match);
    $file[] = $match[1];

?>

instead of
$file = file($file_path);

If line-ending is "\n",
$pattern1 = mb_convert_encoding('[^\n]*\n', $to_encoding, $from_encoding);
bingo at dingo dot com 14-Oct-2013 12:36
To write all the lines of the file in other words to read the file line by line you can write the code like this:
<?php
$names=file('name.txt');
// To check the number of lines
echo count($names).'<br>';
foreach($names as $name)
{
   echo $name.'<br>';
}
?>

this example is so basic to understand how it's working. I hope it will help many beginners.

Regards,
Bingo
twichi at web dot de 13-Sep-2011 12:33
read from CSV data (file) into an array with named keys

... with or without 1st row = header (keys)
(see 4th parameter of function call as  true / false)

<?php
// --------------------------------------------------------------

function csv_in_array($url,$delm=";",$encl="\"",$head=false) {
   
    $csvxrow = file($url);   // ---- csv rows to array ----
   
    $csvxrow[0] = chop($csvxrow[0]);
    $csvxrow[0] = str_replace($encl,'',$csvxrow[0]);
    $keydata = explode($delm,$csvxrow[0]);
    $keynumb = count($keydata);
   
    if ($head === true) {
    $anzdata = count($csvxrow);
    $z=0;
    for($x=1; $x<$anzdata; $x++) {
        $csvxrow[$x] = chop($csvxrow[$x]);
        $csvxrow[$x] = str_replace($encl,'',$csvxrow[$x]);
        $csv_data[$x] = explode($delm,$csvxrow[$x]);
        $i=0;
        foreach($keydata as $key) {
            $out[$z][$key] = $csv_data[$x][$i];
            $i++;
            }   
        $z++;
        }
    }
    else {
        $i=0;
        foreach($csvxrow as $item) {
            $item = chop($item);
            $item = str_replace($encl,'',$item);
            $csv_data = explode($delm,$item);
            for ($y=0; $y<$keynumb; $y++) {
               $out[$i][$y] = $csv_data[$y];
            }
        $i++;
        }
    }

return $out;
}

// --------------------------------------------------------------

?>

fuction call with 4 parameters:

(1) = the file with CSV data (url / string)
(2) = colum delimiter (e.g: ; or | or , ...)
(3) = values enclosed by (e.g: ' or " or ^ or ...)
(4) = with or without 1st row = head (true/false)

<?php

// ----- call ------
$csvdata = csv_in_array( $yourcsvfile, ";", "\"", true );
// -----------------

// ----- view ------
echo "<pre>\r\n";
print_r($csvdata);
echo "</pre>\r\n";
// -----------------

?>

PS: also see: http://php.net/manual/de/function.fgetcsv.php to read CSV data into an array
... and other file-handling methods

^
d basin 14-Oct-2009 03:47
this may be obvious, but it took me a while to figure out what I was doing wrong. So I wanted to share. I have a file on my "c:\" drive. How do I file() it?

Don't forget the backslash is special and you have to "escape" the backslash i.e. "\\":

<?php

$lines = file("C:\\Documents and Settings\\myfile.txt");

foreach($lines as $line)
{
    echo($line);
}

?>

hope this helps...
jon+spamcheck at phpsitesolutions dot com 16-Apr-2008 01:03
A user suggested using rtrim always, due to the line ending conflict with files that have an EOL that differs from the server EOL.

Using rtrim with it's default character replacement is a bad solution though, as it removes all whitespace in addition to the '\r' and '\n' characters.

A good solution using rtrim follows:

<?php
$line = rtrim($line, "\r\n") . PHP_EOL;
?>

This removes only EOL characters, and replaces with the server's EOL character, thus making preg_* work fine when matching the EOL ($)
vbchris at gmail dot com 16-Feb-2008 01:15
If you're getting "failed to open stream: Permission denied" when trying to use either file() or fopen() to access files on another server. Check your host doesn't have any firewall restrictions in-place which prevent outbound connections. This is the case with my host Aplus.net
Reversed: moc dot liamg at senroc dot werdna 12-Jul-2007 02:25
This note applies to PHP 5.1.6 under Windows (although may apply to other versions).

It appears that the 'FILE_IGNORE_NEW_LINES' flag doesn't remove newlines properly when reading Windows-style text files, i.e. files whose lines end in '\r\n'.

Solution: Always use 'rtrim()' in preference to 'FILE_IGNORE_NEW_LINES'.
info at carstanje dot com 28-Nov-2006 12:33
Using file() for reading large text files > 10 Mb gives problems, therefore you should use this instead. It is much slower but it works fine. $lines will return an array with all the lines.

<?php
$handle = @fopen('yourfile...', "r");
if ($handle) {
   while (!feof($handle)) {
       $lines[] = fgets($handle, 4096);
   }
   fclose($handle);
}
?>
justin at visunet dot ie 20-Mar-2003 09:36
Note: Now that file() is binary safe it is 'much' slower than it used to be. If you are planning to read large files it may be worth your while using fgets() instead of file() For example:

<?php
$fd = fopen ("log_file.txt", "r");
while (!feof ($fd))
{
   $buffer = fgets($fd, 4096);
   $lines[] = $buffer;
}
fclose ($fd);
?>

The resulting array is $lines.

I did a test on a 200,000 line file. It took seconds with fgets()  compared to minutes with file().

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