This article will take you through file and directory operations in PHP

How does PHP perform file and directory operations? The following article will give you an in-depth understanding of HP file and directory operations. I hope it will be helpful to you!

Path and disk operations

---

Relative path and absolute path

Absolute path: The path where the drive letter of the current file is located is the starting point

For example:
For example, picture 1.png

The absolute path of this picture is

D:\Google\123\1.png

Let’s explain the content represented by this string of paths separately

• D: (referring to the drive letter
• \ (the one with the table is the directory separator
• Tip: (windows operating system Supports forward slashes and backslashes, other systems support forward slashes /, so forward slashes can reduce compatibility issues)

Relative path: With the location of the file to be operated on The directory is the starting path

This is arelative concept, different reference objects write different paths

Why do you say that
Let’s give an example:
Suppose we use 1.png as a reference

##1.txt

• ./1.txt（There is a dot before 1.）

2.txt

• ../2.txt (two dots before 2)

  Explain it

1.txt is
• a file in the same directory, so only one dot is needed in front, and this dot represents the current directory
2.txt is the
• lower directory, 1.png is the upper directory of 2.txt, the two dots here represent the upper directory
• believe it Everyone already knows about relative paths and absolute paths

Getting file path information

---

We need to understand it first Some concepts

Path:

/love/xianyu.txt

Directory name (dirname ) is /love
• with the file extension name (basename) being xianyu.txt
• the extension name (extension) being .txt
• the file name (filename) being xianyu

Enter the text below

pathinfo()

In order to obtain

Specified path and file name, you can use the pathinfo() function, this function will return an associative array

<?php
$xianyu = "/love/xianyu.php";
$result = pathinfo($xianyu);
foreach($result as $key=>$value){
    echo "$key=>$value\n";
}
?>
/*
输出：
dirname=>/love
basename=>xianyu.php
extension=>php
filename=>xianyu
*/

Quickly obtain the file name: basename()

##basename()

Function, Quickly obtain the file name part of the specified file without reading from the array

<?php
$xianyu = "/love/xianyu.php";
echo $filepath."中的文件名是:".basename($xianyu);
?>
/*
中的文件名是:xianyu.php
*/

Quickly obtain the directory part of the path: dirname()

Use the

dirname()

function to quickly obtain it Specify the directory part of the specified file

<?php
$filepath = "/love/xianyu.php";
echo $filepath."中的路径部分是:". dirname($filepath);
?>
/*
/love/xianyu.php中的路径部分是:/love
*/

Directory operation

---

Opening and closing directories

Handle:

opendir(), closedir()

The handle can be considered as a

return value

. With the handle, you can operate on the open directory

<?php
$dir = "images";
if($dir_handle = opendir($dir))
{
echo "获取目录句柄成功!";
closedir($dir_handle); //记得释放句柄
}
else
{
echo "打开目录错误";
}
?>

Open the images directory

##Release handle

• Why release the handle? If you don't release the handle, it's like you and a bunch of people are writing in a notebook. If you take it away and don't put it back, others can't write. So releasing the handle can save server resources

创建目录

<?php
mkdir("123")
?>

删除目录

<?php
rmdir("123")
?>

获取当前工作目录

<?php
echo getcwd()
?>

改变当前工作目录

<?php
echo getcwd() . &#39;<br>&#39;; // 显示当前目录
chdir(&#39;hhh&#39;); //改变当前目录
echo getcwd() . &#39;<br>&#39;; // 显示当前目录
?>

获取目录句柄条目

• readdir()

将一个参数名作为参数传递给函数readdir()，这个函数能返回目录下所有子目录和文件

注意:调用一次返回一个!!

<?php
if ($handle = opendir(&#39;.&#39;)) {
while (false !== ($file = readdir($handle))) {
echo "$file\n";
}
closedir($handle);
}
?>



读取目录条目

• scandir()

直接返回指定目录下的文件和子目录，并且按照要求排序(默认字母升序)

<?php
$dir1 = scandir("D:\新建文件夹 (2)");
$dir2 = scandir("D:\新建文件夹 (2)",1);//降序排列
print_r($dir1);
print_r($dir2)
?>





文件操作

---

操作文件的一般步骤即：打开，读取或写入，关闭

由于目录和文件本质上都属于文件，除了使用函数不同，很多操作都是相通的

一般操作

判断文件是否存在

<?php
if(file_exists("test.txt"))
{
//如果文件存在就执行操作
}
?>
//如果文件存在返回true，不存在返回false

创建，打开，关闭文件

• fopen(), fclose()

<?php
//以只读方式打开文件，将文件指针指向文件头
$handle = fopen("test.txt", "r");
//以读写方式打开，将文件指针指向文件头
$handle = fopen("test.txt", "r+");
//以写入方式打开，将文件指针指向文件头，并将文件大小截为0。如果文件不存在则尝试创建。
$handle = fopen("test.txt", "w");
//以读写方式打开，将文件指针指向文件头，并将文件大小截为0。如果文件不存在则尝试创建。
$handle = fopen("test.txt", "w+");
//以写入方式打开文件，将文件指针指向文件末尾。如果文件不存在则尝试创建。
$handle = fopen("test.txt", "a");
//以读写方式打开文件，将文件指针指向文件末尾。如果文件不存在则尝试创建。
$handle = fopen("test.txt", "a+");
fclose()
?>

读取文件

• fread(), file_get_contents(), file()

<?php
//需要使用fopen，fread，fclose来进行文件的读取操作
$filename = "test.txt";
$handle = fopen($filename, "r");
$contents = fread($handle, filesize($filename)); //fread需要传入两个参数，第一个参数为
文件句柄，第二个参数为最大读取的字节数
fclose($handle);
//更加简洁的方式
file_get_contents($filename)
?>

写入文件

• fwrite(), file_put_contents()

<?php
//需要fopen,fwrite,fclose来进行文件的写入操作
$handle = fopen("test.txt","w");
fwrite($handle,"添加文字到文件中");//fwrite接受两个参数作为输入,$handle为文件句柄，"添加文
字到文件中"为需要写入的内容
fclose($handle);
//更加简洁的方式
file_put_contents("test.txt", "使用file_put_contents()函数写入的内容")
?>

文件和目录基本操作

删除文件

• unlink()

<?php
$file = "temp.txt";
unlink($file);
?>

复制文件

• copy()

<?php
$sourceFile = "html/cache.txt"; //被复制的文件必须确保存在
$targetFile = "html/copyCache.txt";
copy($sourceFile, $targetFile)
?>

移动，重命名文件或目录

• rename()

<?php
//使用rename()函数重命名一个文件或目录
rename(&#39;test.txt&#39;, &#39;rename.txt&#39;) //将test.txt文件重命名为rename.txt
rename(&#39;test&#39;,&#39;rename&#39;) //将test目录重命名为rename
//使用rename()函数移动文件,并改名
rename("test.txt","test/a.txt");//将test.txt移动到test文件夹下，并改名为a.txt
//使用rename()函数移动目录到目标目录
rename("test","html/test");
?>

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