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<?php
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<p>/<span class="hljs-comment">/**</p>
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<p>Correct Use of <code>filetypeif (file_exists("data.txt")) {
echo "File exists";
} else {
echo "File does not exist";
}
Common mistakes:
Assuming file_exists() only checks files, not directories.
Ignoring permission issues that lead to false negatives (file exists but returns false).
Proper Use of filetype()
filetype() returns the type of a given path as a string, such as:
file for a regular file
dir for a directory
Other types like block, char, fifo, link, socket may appear depending on the system
You must ensure the path exists before calling it; otherwise, it will generate a warning. Therefore, it is common to use file_exists() first.
Example:
$path = "data.txt";
if (file_exists($path)) {
echo "Type is: " . filetype($path);
} else {
echo "Path does not exist";
}
Common mistakes:
Calling filetype() without first checking if the file exists, causing PHP warnings.
Best Practices for Combined Use
When you need to both check if a path exists and distinguish whether it is a file or directory, you can write:
$path = "uploads";
if (!file_exists($path)) {
echo "Path does not exist";
} else {
$type = filetype($path);
if ($type === "file") {
echo "This is a file";
} elseif ($type === "dir") {
echo "This is a directory";
} else {
echo "Other type: " . $type;
}
}
Summary
file_exists() is used to check if a path exists but does not distinguish between files and directories.
filetype() is used to determine the type but must be used only when the path exists.
Common mistakes to avoid: ignoring permission issues, misunderstanding return value types, and not checking existence first.
Only by correctly understanding and combining these two functions can you avoid common pitfalls in file operations and improve code robustness and reliability.
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