Users open files in our app through a QFileDialog. The order of the filenames is bizarre. What is determining the sorting order, and how can we make it sort by filenames, or otherwise impose our own sorting, perhaps giving it a pointer to our own comparison function?
The documentation and online forums haven't been helpful. Unless it's well hidden, there doesn't seem to be any sorting method, property, etc.
This is a primarily Linux app, but also runs on Macs. (I know nothing about Mac.)
Here is the juicy part of the source code:
QtFileDialog chooser(parent, caption, directory, filter);
/// QtFileDialog is our class derived from QFileDialog
chooser.setModal(true);
chooser.setAcceptMode(acceptMode);
chooser.setFileMode(fileMode);
QStringList hist = chooser.history();
chooser.setHistory(hist);
/* point "x" */
if(chooser.exec()) {
QStringList files = chooser.selectedFiles();
...blah blah blah...
From one of the answers, I tried an evil experiment, adding this ill-informed guesswork code at "point x":
QSortFilterProxyModel *sorter = new QSortFilterProxyModel();
sorter->sort(1); // ???
chooser.setProxyModel(sorter);
But this crashed spectacularly at a point about 33 subroutine calls deep from this level of code. I admit, even after reading the Qt4 documentation and sample code, I have no idea of the proper usage of QSortFilterProxyModel.
Are you using QFileDialog by calling exec()? If you are, you should have a button to switch the view to Detail View. This will give you some column headers that you can click on to sort the files. It should remember that mode the next time the dialog opens but you can force it by calling setViewMode(QFileDialog::Detail) before calling exec().
An alternative is to call the static function QFileDialog::getOpenFileName() which will open a file dialog that is native to the OS on which you are running. Your users may like the familiarity of this option better.
Update 1:
About sort order in screen cap from OP:
This screen capture is actually showing a sorted list. I don't know if the listing behaviour is originating from the Qt dialog or the underlying file system but I know Windows XP and later do it this way.
When sorting filenames with embedded numbers, any runs of consecutive digits are treated as a single number. With the more classic plain string sorting, files would be sorted like this:
A_A_10e0
A_A_9a05
Going character by character, the first 1 sorts before the 9.
.. But with numerical interpretation (as in Windows 7 at least), they are sorted as:
A_A_9a05
A_A_10e0
The 9 sorts before the 10.
So, the sorting you are seeing is alphabetical with numerical interpretation and not just straight character by character. Some deep digging may be required to see if that is Qt behaviour or OS behaviour and whether or not it can be configured.
Update 2:
The QSortFilterProxyModel will sort the strings alphabetically by default so there is not much work to using it to get the behavior you are looking for. Use the following code where you have "point x" in your example.. (you almost had it :)
QSortFilterProxyModel *sorter = new QSortFilterProxyModel();
sorter->setDynamicSortFilter(true); // This ensures the proxy will resort when the model changes
chooser.setProxyModel(sorter);
I think what you need to do is create a QSortFilterProxyModel which you then set in your QFileDialog with QFileDialog::setProxyModel(QAbstractProxyModel * proxyModel)
Here are some relevant links to the Qt 4.6 docs about it.
http://doc.trolltech.com/4.6/qfiledialog.html#setProxyModel
http://doc.trolltech.com/4.6/qsortfilterproxymodel.html#details
I don't think it depends upon the implementation of Qt libraries... But upon the Native OS implementation..
For example in Windows,
if you use QFileDialog, it will display the Files and Directories by Name sorted.. It is the same when used in other applications. In the sense that, if you try to open a file through MS- Word, it indeed displays the Files and directories as Name sorted by default..
And am not sure about other environments since am not used to them...
But in Windows, you can change the sorted order by right-click in the area of Files and Directories display and can select the options you like.. For e.g like Name,size,type, modified... And also which is similar, when you use an MS-Word application...
So, I believe it does depend on the Native OS implementation and not on QFileDialog's...
Related
I'm using jupyter and pandas read_sql, this works fine but looks ugly.
for instance I have a query:
SELECT *
FROM table_a AS a
LIMIT 10;
I could show it nicely in a markdown cell as so:
``` mysql
SELECT *
FROM table_a AS a
LIMIT 10;
```
and I could execute it in a code cell as so:
pd.read_sql('SELECT * FROM table_a AS a LIMIT 10;', conn)
this involves copy/paste and displaying the query twice (not too good if I want to simply export my notebook to a pdf report)
is there a way to avoid the duplication by reading the markdown text into a string python variable, or any other way?
The cellmagic answer cited by #Micah Kornfield in the question comments may be a good fit for many situations. In the question however it is said that it is desirable to avoid duplicates. Let's imagine that the SQL is huge and we don't want see the same query more than once.
Unfortunatelly right now in 2021 there's no easy solution for this. In a jupyter notebook there are two worlds, the backend which is the kernel and in our case runs python, and the frontend which runs javascript. Only javascript sees the markdown cells. It is possible to make the backend and frontend communicate with each other, those methods are usually a little hacky, but anyway we will rely on some of them.
I have written a script that does our job in two different ways, which will probably bring similar results. I will call those methods the file read method and the javascript method.
First, please save the following file markdown.py in the same folder as the ipython (we are using a separate file because you specified that your notebook willl eventually go to a report and it is undesirable to have this script together with the notebook):
from IPython.display import Javascript
from urllib.parse import unquote
from json import loads as jsonloads
def markread(cellnumber,notebookname=None,callbackvar=None):
try:
if type(cellnumber) is int:# maybe check if (varname in globals()):
if callbackvar is not None and type(callbackvar) is str:
return Javascript("const mdtjs = Jupyter.notebook.get_cells().filter(c=>c.cell_type==\"markdown\")["+str(cellnumber)+"].get_text(); IPython.notebook.kernel.execute(\"mdtp = unquote('\"+encodeURI(mdtjs)+\"');mdtp=mdtp[mdtp.find('\\\\n',mdtp.find('```'))+1:min(mdtp.rfind('\\\\n'),mdtp.rfind('```'))].strip();"+callbackvar+"=mdtp;del mdtp\");")
if notebookname is not None and type (notebookname) is str:
if not notebookname.endswith('.ipynb'):
notebookname += '.ipynb'
with open(notebookname) as f:
j = jsonloads(f.read())
mdts = [''.join(c['source'][1:]).strip().strip('`').strip() for c in j['cells'] if c['cell_type']=='markdown']
return mdts[cellnumber]
except:
return None
return None
Now back to the notebook, to load the script, you have to import it:
from markdown import markread, unquote
The unquote is needed to use the javascript method, otherwhise you can skip it.
1. File read method:
Usage:
marktext = markread(2, notebookname='mynotebookname')
Here marktext will get the value from the third markdown cell in the mynotebookname (third because we live in a zero-indexed world, so 2 means third; if you skip '.ipynb' extension in the notebookname as in this case it will be automatically appended). Important - this method reads the notebook file writen on disk and not the hot state of things. If you changed anything since last save, things may go wrong.
2. Javascript method:
Usage:
markread(1, callbackvar='marktext')
Here we write the value of our second markdown cell to a variable called marktext. Javascript method is trickier - it is async, so we have to send the name of the variable that we want to write to (must be a string representing its name, not the variable itself). Is is important to know also that markread must be the last command in the cell due to a limitation in javascript invoking.
How it works
Internally, the file read method just reads the notebook file which is json, picks the value from 'cells' and filters out the ones which are markdown.
The javascript method however is more complex. It invokes JS because JS has access to the cells including markdown, so JS reads cells values (from the Jupyter.notebook.get_cells), filters the markdown ones, invoke python back and send back those markdown cells - url enconded. Those encoded cells are decoded back and assigned to the callbackvar. In both methods I made some assumptions that may not be correct about trimming the start and the end of the cell value (the ``` and whitespaces).
There are ways to improve the code, for example making it auto detect the notebook name for the file read method, but it involves even more hacks, relying again on javascript to get the notebook name or making an call to the api on port 8888, but having to deal with session password. I believe the most important is covered already by our script. If one method does not work, you will probably still have the other.
I need to a keymap for my embedded QWSServer application.
Using environmental variables like this
QWS_KEYBOARD="TTY:keymap=/german_keyboard.qmap"
export QWS_KEYBOARD
works, but isn't optimal for me.
I tried to set it from code using
QWSServer* wsServer = QWSServer::instance();
QWSKeyboardHandler * kh = QKbdDriverFactory::create("TTY", "keymap=/german_keymap.qmap");
wsServer->setKeyboardHandler(kh);
as mentioned here.
However, it is not working. Any ideas how to fix it?
It actually looks like you couldn't do it. According to this manual page you can only set the driver and device for a keyboard handler, but no additional options like keymap.
In this arcticle about the keymap thing only the environment variable way ist mentioned, too.
Because of this, the answer here seems to be wrong.
Beware: According to this answer, Qt5 doesn't have QWS and all QWS-related APIs have been removed.
You can try:
QWSServer::instance()->closeKeyboard();
QWSKeyboardHandler * kh = QKbdDriverFactory::create("TTY", "keymap=/german_keymap.qmap");
It works for me, but only the first time, if I want to change the layout a second time, the closeKeyboard() will crash, as it's trying to delete the driver defined by QWS_KEYBOARD, and it has already been deleted the first time.
I want to achieve something like the following:
Where I can select multiple folders across multiple drives and retrieve the folder paths of those selected. Qt only has a crude multi-folder selection feature, but it does not support selected folders from other drives etc.
Can anyone guide me on how to create such a dialog? Better yet, does any one have any sample code I could use (this is an extension to an old project, and I'd much rather save my time and not re-invent the wheel!)
Thanks
You can use QFileSystemModel for represent filesystem on QTreeView. This example explains how to do that.
For checkbox issue, according to this list archives:
The simplest way to do this (I can think of, at least) is to subclass
QDirModel and override flags, data and setData:
flags should add Qt::ItemIsUserCheckable to the returned flags
data should return the Qt::CheckState of the queried index if the role parameter is Qt::CheckStateRole
setData should store the check state of the index
Or, even better, this should work with a QProxyModel pretty much the
same way (after all, "favor object composition over class
inheritance").
Note that QDirModel class is obsolete. You may not use that on newer Qt versions. I recommend to use QFileSystemModel.
####### Retrieve a list of directories with wxPython-Phoenix - tested on python3.5
### installation instruction for wxPython-Phoenix : https://wiki.wxpython.org/How%20to%20install%20wxPython#Installing_wxPython-Phoenix_using_pip
### modified from : https://wxpython.org/Phoenix/docs/html/wx.lib.agw.multidirdialog.html
import os
import wx
import wx.lib.agw.multidirdialog as MDD
# Our normal wxApp-derived class, as usual
app = wx.App(0)
dlg = MDD.MultiDirDialog(None, title="Custom MultiDirDialog", defaultPath=os.getcwd(), # defaultPath="C:/Users/users/Desktop/",
agwStyle=MDD.DD_MULTIPLE|MDD.DD_DIR_MUST_EXIST)
if dlg.ShowModal() != wx.ID_OK:
print("You Cancelled The Dialog!")
dlg.Destroy()
paths = dlg.GetPaths()
#Print directories' path and files
for path in enumerate(paths):
print(path[1])
directory= path[1].replace('OS (C:)','C:')
print(directory)
for file in os.listdir(directory):
print(file)
dlg.Destroy()
app.MainLoop()
I'm working with QDomElement and QDomDocument to export data to XML. When I do this, the attributes get written in the correct order:
element.setAttribute("xRepeat", xrepeat);
element.setAttribute("yRepeat", yrepeat);
This outputs something like xRepeat="3" yRepeat="8". Then I tried this...
element.setAttribute("xrepeat", xrepeat);
element.setAttribute("yrepeat", yrepeat);
The resulting output is yrepeat="8" xrepeat="3". Is there a reason why the attributes are being written in reversed order now? I already did the usual clean/qmake/build routine in my IDE (Qt Creator) to make sure that the compiler's "only rebuild what was changed" feature wasn't doing any weird stuff
The order of attribute specifications in a start-tag or empty-element tag is not significant. Don't rely on software that requires a specfic order.
Cat Plus Plus is correct.
QDomElement uses a QHash underneath to store element attributes. QT Doc states that
With QHash, the items are arbitrarily
ordered
When you change key you also change the order.
I'm working in some old code which was originally designed for handling two different kinds of files. I was recently tasked with adding a new kind of file to this code. Most of my problems were solved by filling out an extensive XML file with a new entry that handled everything from what lists were named to how the file is written in plural lower case. But this ended up being insufficient, as there were maybe 50 different places in 24 different code files where I had to update hardcoded switch-statements that only branched for the original two file types.
Unfortunately there is no consistency in this; there are methods which operate half from the XML file, and half off of hardcode. Some of the files which look like they would operate off of the XML file don't, and some that I would expect that I'd need to update the hardcode don't need it. So the only way to find the majority of these is to run through testing the whole system when only part of it is operational, finding that one step to fix (when I'm lucky that error logging actually tells me what is going on), and then running the whole thing again. This wastes time testing the parts of the code which are already confirmed to work, time better spent testing the new parts I have to add on top of it all.
It's a hassle and a half, and to my luck I can expect that I will have to add yet another new kind of file in the near future.
Are there any solutions out there which can aid in this kind of endeavour? Something which I can input some parameters of current features, document what points in a whole code project actually need to be updated, and run something nice the next time I need to add a new feature to the code. It needn't even be fully automated, something that'll help me navigate straight to the specific points in everything and maybe even record what kind of parameters need to be loaded.
Doubt it matters specifically, but the code is comprised of ASP.NET pages, some ASP.NET controls, hundreds of C# code files, and a handful of additional XML files. It's all currently in a couple big Visual Studio 2008 projects.
Not exactly what you are describing, but if you can introduce a seam into the code and lay down some interfaces you can break out and mock, a suite of unit/integration tests would go a long way to helping you modify old code you may not fully understand well.
I completely agree with the comment about using Michael Feathers' book to learn how to wedge new tests into legacy code. I'd also strongly recommend Refactoring, by Martin Fowler. What it sounds like you need to do for your code is to implement the "Replace conditionals with polymorphism" refactoring.
I imagine your code today looks somewhat like this:
if (filetype == 23)
{
type23parser.parse(file);
}
else if (filetype == 69)
{
filestore = type69reader.read(file);
File newfile = convertFSto23(filestore);
type23parser.parse(newfile);
}
What you want to do is to abstract away all the "if (type == foo)" kinds of logic into strategy patterns that are created in a factory.
class FileRules : pReader(NULL), pParser(NULL)
{
private:
FileReaderRules *pReader;
FileParserRules *pParser;
public:
void read(File* inFile) {pReader->read(inFile);};
void parse(File* inFile) {pParser->parse(inFile);};
};
class FileRulesFactory
{
FileRules* GetRules(int inputFiletype, int parserType)
{
switch (inputFiletype)
{
case 23:
pReader = new ASCIIReader;
break;
case 69:
pReader = new EBCDICReader;
break;
}
switch (parserType)
... etc...
then your main line of code looks like this:
FileRules* rules = FileRulesFactory.GetRules(filetype, parsertype);
rules.read(file);
rules.parse(file);
Pull off this refactoring, and adding a new set of file types, parsers, readers, etc., becomes as simple as writing one exclusive to your new type.
Of course, go read the book. I vastly oversimplified it here, and probably got stuff wrong, but you should get the general idea of how to approach it from this. I can also recommend another book, "Head First Design Patterns", which has a great section on the Factory patterns (if you like those "Head First" kinds of books.)