file()

(PHP 4, PHP 5, PHP 7)

把整个文件读入一个数组中

说明

把整个文件读入一个数组中。

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

参数

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。

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 thestream_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()returnsFALSE.

Note:

Each line in the resulting array will include the line ending,unlessFILE_IGNORE_NEW_LINESis used, so you still need to usertrim()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

范例

Example #1file()例子

注释

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

• readfile() 输出文件
• fopen() 打开文件或者 URL
• fsockopen() 打开一个网络连接或者一个Unix套接字连接
• popen() 打开进程文件指针
• file_get_contents() 将整个文件读入一个字符串
• include- include
• stream_context_create() 创建资源流上下文

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:

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

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. "\\":
 
hope this helps...

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).

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 '
';
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 '
';
result:
failure
success

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) 

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) 

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

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....

("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"),

instead of 
$file = file($file_path);
If line-ending is "\n",
$pattern1 = mb_convert_encoding('[^\n]*\n', $to_encoding, $from_encoding);

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:

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'.

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:

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().

Here's my CSV converter
supports Header and trims all fields
Note: Headers must be not empty! 

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