QDir — PyQt Documentation v5.15.7 (original) (raw)

PyQt5.QtCore.QDir

Description¶

The QDir class provides access to directory structures and their contents.

A QDir is used to manipulate path names, access information regarding paths and files, and manipulate the underlying file system. It can also be used to access Qt’s resource system.

Qt uses “/” as a universal directory separator in the same way that “/” is used as a path separator in URLs. If you always use “/” as a directory separator, Qt will translate your paths to conform to the underlying operating system.

A QDir can point to a file using either a relative or an absolute path. Absolute paths begin with the directory separator (optionally preceded by a drive specification under Windows). Relative file names begin with a directory name or a file name and specify a path relative to the current directory.

Examples of absolute paths:

QDir("/home/user/Documents")

QDir("C:/Documents and Settings")

On Windows, the second example above will be translated to C:\Documents and Settings when used to access files.

Examples of relative paths:

QDir("images/landscape.png")

You can use the isRelative() or isAbsolute() functions to check if a QDir is using a relative or an absolute file path. Call makeAbsolute() to convert a relative QDir to an absolute one.

Navigation and Directory Operations¶

A directory’s path can be obtained with the path() function, and a new path set with the setPath() function. The absolute path to a directory is found by calling absolutePath().

The name of a directory is found using the dirName() function. This typically returns the last element in the absolute path that specifies the location of the directory. However, it can also return “.” if the QDir represents the current directory.

QDir("Documents/Letters/Applications").dirName() // "Applications"

QDir().dirName() // "."

The path for a directory can also be changed with the cd() and cdUp() functions, both of which operate like familiar shell commands. When cd() is called with the name of an existing directory, the QDir object changes directory so that it represents that directory instead. The cdUp() function changes the directory of the QDir object so that it refers to its parent directory; i.e. cd(“..”) is equivalent to cdUp().

Directories can be created with mkdir(), renamed with rename(), and removed with rmdir().

You can test for the presence of a directory with a given name by using exists(), and the properties of a directory can be tested with isReadable(), isAbsolute(), isRelative(), and isRoot().

The refresh() function re-reads the directory’s data from disk.

Files and Directory Contents¶

Directories contain a number of entries, representing files, directories, and symbolic links. The number of entries in a directory is returned by count(). A string list of the names of all the entries in a directory can be obtained with entryList(). If you need information about each entry, use entryInfoList() to obtain a list of QFileInfo objects.

Paths to files and directories within a directory can be constructed using filePath() and absoluteFilePath(). The filePath() function returns a path to the specified file or directory relative to the path of the QDir object; absoluteFilePath() returns an absolute path to the specified file or directory. Neither of these functions checks for the existence of files or directory; they only construct paths.

QDir directory("Documents/Letters");

QString path = directory.filePath("contents.txt");

QString absolutePath = directory.absoluteFilePath("contents.txt");

Files can be removed by using the remove() function. Directories cannot be removed in the same way as files; use rmdir() to remove them instead.

It is possible to reduce the number of entries returned by entryList() and entryInfoList() by applying filters to a QDir object. You can apply a name filter to specify a pattern with wildcards that file names need to match, an attribute filter that selects properties of entries and can distinguish between files and directories, and a sort order.

Name filters are lists of strings that are passed to setNameFilters(). Attribute filters consist of a bitwise OR combination of Filters, and these are specified when calling setFilter(). The sort order is specified using setSorting() with a bitwise OR combination of SortFlags.

You can test to see if a filename matches a filter using the match() function.

Filter and sort order flags may also be specified when calling entryList() and entryInfoList() in order to override previously defined behavior.

The Current Directory and Other Special Paths¶

Access to some common directories is provided with a number of static functions that return QDir objects. There are also corresponding functions for these that return strings:

The setCurrent() static function can also be used to set the application’s working directory.

If you want to find the directory containing the application’s executable, see applicationDirPath().

The drives() static function provides a list of root directories for each device that contains a filing system. On Unix systems this returns a list containing a single root directory “/”; on Windows the list will usually contain C:/, and possibly other drive letters such as D:/, depending on the configuration of the user’s system.

Path Manipulation and Strings¶

Paths containing “.” elements that reference the current directory at that point in the path, “..” elements that reference the parent directory, and symbolic links can be reduced to a canonical form using the canonicalPath() function.

Paths can also be simplified by using cleanPath() to remove redundant “/” and “..” elements.

It is sometimes necessary to be able to show a path in the native representation for the user’s platform. The static toNativeSeparators() function returns a copy of the specified path in which each directory separator is replaced by the appropriate separator for the underlying operating system.

Examples¶

Check if a directory exists:

QDir dir("example");

if (!dir.exists())

qWarning("Cannot find the example directory");

(We could also use the static convenience function exists().)

Traversing directories and reading a file:

QDir dir = QDir::root(); // "/"

if (!dir.cd("tmp")) { // "/tmp"

qWarning("Cannot find the "/tmp" directory");

} else {

QFile file(dir.filePath("ex1.txt")); // "/tmp/ex1.txt"

if (!file.open(QIODevice::ReadWrite))

qWarning("Cannot create the file %s", file.name());

}

A program that lists all the files in the current directory (excluding symbolic links), sorted by size, smallest first:

#include

#include

int main(int argc, char *argv[])

{

QCoreApplication app(argc, argv);

QDir dir;

dir.setFilter(QDir::Files | QDir::Hidden | QDir::NoSymLinks);

dir.setSorting(QDir::Size | QDir::Reversed);

QFileInfoList list = dir.entryInfoList();

std::cout << " Bytes Filename" << std::endl;

for (int i = 0; i < list.size(); ++i) {

QFileInfo fileInfo = list.at(i);

std::cout << qPrintable(QString("%1 %2").arg(fileInfo.size(), 10)

.arg(fileInfo.fileName()));

std::cout << std::endl;

}

return 0;

}

Classes¶

Enums¶

Filter

This enum describes the filtering options available to QDir; e.g. for entryList() and entryInfoList(). The filter value is specified by combining values from the following list using the bitwise OR operator:

Functions that use Filter enum values to filter lists of files and directories will include symbolic links to files and directories unless you set the value.

A default constructed QDir will not filter out files based on their permissions, so entryList() and entryInfoList() will return all files that are readable, writable, executable, or any combination of the three. This makes the default easy to write, and at the same time useful.

For example, setting the Readable, Writable, and Files flags allows all files to be listed for which the application has read access, write access or both. If the Dirs and Drives flags are also included in this combination then all drives, directories, all files that the application can read, write, or execute, and symlinks to such files/directories can be listed.

To retrieve the permissons for a directory, use the entryInfoList() function to get the associated QFileInfo objects and then use the QFileInfo::permissons() to obtain the permissions and ownership for each file.

SortFlag

This enum describes the sort options available to QDir, e.g. for entryList() and entryInfoList(). The sort value is specified by OR-ing together values from the following list:

You can only specify one of the first four.

If you specify both and Reversed, directories are still put first, but in reverse order; the files will be listed after the directories, again in reverse order.

Methods¶

__init__(QDir)

Constructs a QDir object that is a copy of the QDir object for directory dir.

__init__(path: str = '')

Constructs a QDir pointing to the given directory path. If path is empty the program’s working directory, (“.”), is used.

__init__(str, str, sort: SortFlags = QDir.Name|QDir.IgnoreCase, filters: Filters = AllEntries)

Constructs a QDir with path path, that filters its entries by name using nameFilter and by attributes using filters. It also sorts the names using sort.

The default nameFilter is an empty string, which excludes nothing; the default filters is AllEntries, which also means exclude nothing. The default sort is Name | IgnoreCase, i.e. sort by name case-insensitively.

If path is an empty string, QDir uses “.” (the current directory). If nameFilter is an empty string, QDir uses the name filter “*” (all files).

Note that path need not exist.

absoluteFilePath(str) → str

Returns the absolute path name of a file in the directory. Does not check if the file actually exists in the directory; but see exists(). Redundant multiple separators or “.” and “..” directories in fileName are not removed (see cleanPath()).

absolutePath() → str

Returns the absolute path (a path that starts with “/” or with a drive specification), which may contain symbolic links, but never contains redundant “.”, “..” or multiple separators.

@staticmethod
addSearchPath(str, str)

Adds path to the search path for prefix.

See also

setSearchPaths().

canonicalPath() → str

Returns the canonical path, i.e. a path without symbolic links or redundant “.” or “..” elements.

On systems that do not have symbolic links this function will always return the same string that absolutePath() returns. If the canonical path does not exist (normally due to dangling symbolic links) returns an empty string.

Example:

QString bin = "/local/bin"; // where /local/bin is a symlink to /usr/bin

QDir binDir(bin);

QString canonicalBin = binDir.canonicalPath();

// canonicalBin now equals "/usr/bin"

QString ls = "/local/bin/ls"; // where ls is the executable "ls"

QDir lsDir(ls);

QString canonicalLs = lsDir.canonicalPath();

// canonicalLS now equals "/usr/bin/ls".

cd(str) → bool

Changes the QDir’s directory to dirName.

Returns true if the new directory exists; otherwise returns false. Note that the logical operation is not performed if the new directory does not exist.

Calling cd(“..”) is equivalent to calling cdUp().

See also

cdUp(), isReadable(), exists(), path().

cdUp() → bool

Changes directory by moving one directory up from the QDir’s current directory.

Returns true if the new directory exists; otherwise returns false. Note that the logical operation is not performed if the new directory does not exist.

See also

cd(), isReadable(), exists(), path().

@staticmethod
cleanPath(str) → str

Returns path with directory separators normalized (converted to “/”) and redundant ones removed, and “.”s and “..”s resolved (as far as possible).

Symbolic links are kept. This function does not return the canonical path, but rather the simplest version of the input. For example, “./local” becomes “local”, “local/../bin” becomes “bin” and “/local/usr/../bin” becomes “/local/bin”.

__contains__(str) → int

TODO

count() → int

Returns the total number of directories and files in the directory.

Equivalent to entryList()..

See also

operator[](), entryList().

@staticmethod
current() → QDir

@staticmethod
currentPath() → str

Returns the absolute path of the application’s current directory. The current directory is the last directory set with setCurrent() or, if that was never called, the directory at which this application was started at by the parent process.

dirName() → str

Returns the name of the directory; this is not the same as the path, e.g. a directory with the name “mail”, might have the path “/var/spool/mail”. If the directory has no name (e.g. it is the root directory) an empty string is returned.

No check is made to ensure that a directory with this name actually exists; but see exists().

@staticmethod
drives() → List[QFileInfo]

Returns a list of the root directories on this system.

On Windows this returns a list of QFileInfo objects containing “C:/”, “D:/”, etc. On other operating systems, it returns a list containing just one root directory (i.e. “/”).

See also

root(), rootPath().

entryInfoList(filters: Union[Filters, Filter] = NoFilter, sort: Union[SortFlags, SortFlag] = QDir.SortFlag.NoSort) → List[QFileInfo]

TODO

entryInfoList(Iterable[str], filters: Union[Filters, Filter] = NoFilter, sort: Union[SortFlags, SortFlag] = QDir.SortFlag.NoSort) → List[QFileInfo]

TODO

entryList(filters: Union[Filters, Filter] = NoFilter, sort: Union[SortFlags, SortFlag] = QDir.SortFlag.NoSort) → List[str]

TODO

entryList(Iterable[str], filters: Union[Filters, Filter] = NoFilter, sort: Union[SortFlags, SortFlag] = QDir.SortFlag.NoSort) → List[str]

TODO

__eq__(QDir) → bool

TODO

exists() → bool

This is an overloaded function.

Returns true if the directory exists; otherwise returns false. (If a file with the same name is found this function will return false).

The overload of this function that accepts an argument is used to test for the presence of files and directories within a directory.

exists(str) → bool

Returns true if the file called name exists; otherwise returns false.

Unless name contains an absolute file path, the file name is assumed to be relative to the directory itself, so this function is typically used to check for the presence of files within a directory.

filePath(str) → str

Returns the path name of a file in the directory. Does not check if the file actually exists in the directory; but see exists(). If the QDir is relative the returned path name will also be relative. Redundant multiple separators or “.” and “..” directories in fileName are not removed (see cleanPath()).

filter() → Filters

Returns the value set by setFilter()

@staticmethod
fromNativeSeparators(str) → str

Returns pathName using ‘/’ as file separator. On Windows, for instance, (”c:\\winnt\\system32”) returns “c:/winnt/system32”.

The returned string may be the same as the argument on some operating systems, for example on Unix.

__getitem__(int) → str

TODO

__getitem__(slice) → List[str]

TODO

@staticmethod
home() → QDir

TODO

@staticmethod
homePath() → str

Returns the absolute path of the user’s home directory.

Under Windows this function will return the directory of the current user’s profile. Typically, this is:

C:/Documents and Settings/Username

Use the toNativeSeparators() function to convert the separators to the ones that are appropriate for the underlying operating system.

If the directory of the current user’s profile does not exist or cannot be retrieved, the following alternatives will be checked (in the given order) until an existing and available path is found:

1. The path specified by the USERPROFILE environment variable.
2. The path formed by concatenating the HOMEDRIVE and HOMEPATH environment variables.
3. The path specified by the HOME environment variable.
4. The path returned by the rootPath() function (which uses the SystemDrive environment variable)
5. The C:/ directory.

Under non-Windows operating systems the HOME environment variable is used if it exists, otherwise the path returned by the rootPath().

isAbsolute() → bool

TODO

@staticmethod
isAbsolutePath(str) → bool

TODO

isEmpty(filters: Union[Filters, Filter] = QDir.AllEntries|QDir.NoDotAndDotDot) → bool

TODO

isReadable() → bool

Returns true if the directory is readable and we can open files by name; otherwise returns false.

Warning: A false value from this function is not a guarantee that files in the directory are not accessible.

isRelative() → bool

Returns true if the directory path is relative; otherwise returns false. (Under Unix a path is relative if it does not start with a “/”).

@staticmethod
isRelativePath(str) → bool

Returns true if path is relative; returns false if it is absolute.

isRoot() → bool

Returns true if the directory is the root directory; otherwise returns false.

Note: If the directory is a symbolic link to the root directory this function returns false. If you want to test for this use canonicalPath(), e.g.

QDir dir("/tmp/root_link");

dir = dir.canonicalPath();

if (dir.isRoot())

qWarning("It is a root link");

See also

root(), rootPath().

__len__() → int

TODO

@staticmethod
listSeparator() → str

TODO

makeAbsolute() → bool

Converts the directory path to an absolute path. If it is already absolute nothing happens. Returns true if the conversion succeeded; otherwise returns false.

@staticmethod
match(Iterable[str], str) → bool

TODO

@staticmethod
match(str, str) → bool

TODO

mkdir(str) → bool

Creates a sub-directory called dirName.

Returns true on success; otherwise returns false.

If the directory already exists when this function is called, it will return false.

mkpath(str) → bool

Creates the directory path dirPath.

The function will create all parent directories necessary to create the directory.

Returns true if successful; otherwise returns false.

If the path already exists when this function is called, it will return true.

nameFilters() → List[str]

Returns the string list set by setNameFilters()

See also

setNameFilters().

@staticmethod
nameFiltersFromString(str) → List[str]

Returns a list of name filters from the given nameFilter. (If there is more than one filter, each pair of filters is separated by a space or by a semicolon.)

__ne__(QDir) → bool

TODO

path() → str

Returns the path. This may contain symbolic links, but never contains redundant “.”, “..” or multiple separators.

The returned path can be either absolute or relative (see setPath()).

refresh()

Refreshes the directory information.

relativeFilePath(str) → str

Returns the path to fileName relative to the directory.

QDir dir("/home/bob");

QString s;

s = dir.relativeFilePath("images/file.jpg"); // s is "images/file.jpg"

s = dir.relativeFilePath("/home/mary/file.txt"); // s is "../mary/file.txt"

remove(str) → bool

Removes the file, fileName.

Returns true if the file is removed successfully; otherwise returns false.

removeRecursively() → bool

TODO

rename(str, str) → bool

Renames a file or directory from oldName to newName, and returns true if successful; otherwise returns false.

On most file systems, fails only if oldName does not exist, or if a file with the new name already exists. However, there are also other reasons why can fail. For example, on at least one file system fails if newName points to an open file.

If oldName is a file (not a directory) that can’t be renamed right away, Qt will try to copy oldName to newName and remove oldName.

rmdir(str) → bool

Removes the directory specified by dirName.

The directory must be empty for to succeed.

Returns true if successful; otherwise returns false.

rmpath(str) → bool

Removes the directory path dirPath.

The function will remove all parent directories in dirPath, provided that they are empty. This is the opposite of mkpath(dirPath).

Returns true if successful; otherwise returns false.

@staticmethod
root() → QDir

TODO

@staticmethod
rootPath() → str

Returns the absolute path of the root directory.

For Unix operating systems this returns “/”. For Windows file systems this normally returns “c:/”.

@staticmethod
searchPaths(str) → List[str]

Returns the search paths for prefix.

@staticmethod
separator() → str

Returns the native directory separator: “/” under Unix and “\” under Windows.

You do not need to use this function to build file paths. If you always use “/”, Qt will translate your paths to conform to the underlying operating system. If you want to display paths to the user using their operating system’s separator use toNativeSeparators().

See also

listSeparator().

@staticmethod
setCurrent(str) → bool

Sets the application’s current working directory to path. Returns true if the directory was successfully changed; otherwise returns false.

setFilter(Union[Filters, Filter])

Sets the filter used by entryList() and entryInfoList() to filters. The filter is used to specify the kind of files that should be returned by entryList() and entryInfoList(). See Filter.

See also

filter(), setNameFilters().

setNameFilters(Iterable[str])

Sets the name filters used by entryList() and entryInfoList() to the list of filters specified by nameFilters.

Each name filter is a wildcard (globbing) filter that understands \* and ? wildcards. See QRegularExpression Wildcard Matching.

For example, the following code sets three name filters on a QDir to ensure that only files with extensions typically used for C++ source files are listed:

QStringList filters;

filters << ".cpp" << ".cxx" << "*.cc";

dir.setNameFilters(filters);

See also

nameFilters(), setFilter().

setPath(str)

Sets the path of the directory to path. The path is cleaned of redundant “.”, “..” and of multiple separators. No check is made to see whether a directory with this path actually exists; but you can check for yourself using exists().

The path can be either absolute or relative. Absolute paths begin with the directory separator “/” (optionally preceded by a drive specification under Windows). Relative file names begin with a directory name or a file name and specify a path relative to the current directory. An example of an absolute path is the string “/tmp/quartz”, a relative path might look like “src/fatlib”.

@staticmethod
setSearchPaths(str, Iterable[str])

Sets or replaces Qt’s search paths for file names with the prefix prefix to searchPaths.

To specify a prefix for a file name, prepend the prefix followed by a single colon (e.g., “images:undo.png”, “xmldocs:books.xml”). prefix can only contain letters or numbers (e.g., it cannot contain a colon, nor a slash).

Qt uses this search path to locate files with a known prefix. The search path entries are tested in order, starting with the first entry.

QDir::setSearchPaths("icons", QStringList(QDir::homePath() + "/images"));

QDir::setSearchPaths("docs", QStringList(":/embeddedDocuments"));

...

QPixmap pixmap("icons:undo.png"); // will look for undo.png in QDir::homePath() + "/images"

QFile file("docs:design.odf"); // will look in the :/embeddedDocuments resource path

File name prefix must be at least 2 characters long to avoid conflicts with Windows drive letters.

Search paths may contain paths to The Qt Resource System.

setSorting(Union[SortFlags, SortFlag])

Sets the sort order used by entryList() and entryInfoList().

The sort is specified by OR-ing values from the enum SortFlag.

See also

sorting(), SortFlag.

sorting() → SortFlags

Returns the value set by setSorting()

See also

setSorting(), SortFlag.

swap(QDir)

TODO

@staticmethod
temp() → QDir

TODO

@staticmethod
tempPath() → str

Returns the absolute canonical path of the system’s temporary directory.

On Unix/Linux systems this is the path in the TMPDIR environment variable or /tmp if TMPDIR is not defined. On Windows this is usually the path in the TEMP or TMP environment variable. The path returned by this method doesn’t end with a directory separator unless it is the root directory (of a drive).

@staticmethod
toNativeSeparators(str) → str

Returns pathName with the ‘/’ separators converted to separators that are appropriate for the underlying operating system.

On Windows, (“c:/winnt/system32”) returns “c:\winnt\system32”.

The returned string may be the same as the argument on some operating systems, for example on Unix.