(PHP 4, PHP 5, PHP 7, PHP 8)
file — 把整个文件读入一个数组中
$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。
filename文件的路径。
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
FILE_IGNORE_NEW_LINES
FILE_SKIP_EMPTY_LINES
context使用 stream_context_create() 函数创建的上下文资源（resource）。
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。
返回数组形式的文件内容。数组的每个元素对应于文件中的一行（结尾会附加换行符）。
失败时，file() 返回 false。
Note:
除非使用了
FILE_IGNORE_NEW_LINES，否则结果数组中的每一行都将包含行尾。
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。
如果文件不存在，则发出 E_WARNING 级错误。
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);
?>
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。
Be aware that using file() to count lines can cause OOM on the server as it'll allocate all lines into an array.
If you're dealing with files that can have thousands of lines, SplFileObject might be a better idea and with little changes you can get the same result.
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);
My experience is that the function file does uses the cached content if the file has changed....
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 ( $file_array !== false ) {
# code...
echo "success\n"; // executed
} else {
# code...
echo "failure\n";
}
echo '</pre>';
result:
failure
success
If the file you are reading is in CSV format do not use file(), use fgetcsv(). file() will split the file by each newline that it finds, even newlines that appear within a field (i.e. within quotations).
Here's my CSV converter
supports Header and trims all fields
Note: Headers must be not empty!
<?php
function csv2array($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;
}
?>
("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);
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 $name.'<br>';
}
?>
this example is so basic to understand how it's working. I hope it will help many beginners.
Regards,
Bingo
read from CSV data (file) into an array with named keys
... with or without 1st row = header (keys)
(see 4th parameter of function call as true / false)
<?php
// --------------------------------------------------------------
function csv_in_array($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
^
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...
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 ($)
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
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'.
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);
}
?>
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().