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PHP function introduction—file_exists(): Check whether a file or directory exists
Introduction:
In PHP programming, we often need to check whether a file or directory exists in order to perform corresponding processing. PHP's file_exists() function is a function used to check whether the specified file or directory exists.
Syntax:
bool file_exists (string $filename)
Parameters:
Return value:
If the file or directory exists, it returns true; if the file or directory does not exist, it returns false.
Example:
The following is a sample code to demonstrate how to use the file_exists() function to check whether a file or directory exists.
<?php // 检查文件是否存在 $file = 'example.txt'; if (file_exists($file)) { echo "文件存在。"; } else { echo "文件不存在。"; } // 检查目录是否存在 $dir = 'example_dir'; if (file_exists($dir) && is_dir($dir)) { echo "目录存在。"; } else { echo "目录不存在。"; } ?>
In the above example, a file path variable $file is first defined, and the file_exists() function is used to check whether the file exists. If it exists, output "The file exists.", otherwise output "The file does not exist.".
Next, a directory path variable $dir is defined, and the file_exists() function and is_dir() function are used to check whether the directory exists. If it exists and is a directory, output "The directory exists.", otherwise output "The directory does not exist.".
Note:
Summary:
The file_exists() function is an important function in PHP used to check whether a file or directory exists. In daily PHP programming, it is often necessary to determine the existence of files or directories. This function can be easily achieved using the file_exists() function. Whether it is a local file or a remote file, you can use the file_exists() function to check the existence of a file or directory. The return value of this function is a Boolean value indicating whether the file or directory exists. Combined with other file processing functions, further operations on files or directories can be achieved. When using the file_exists() function, pay attention to the reasonable use of conditional judgments to ensure the correctness and safety of the program.
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