AttributeError: 'QString' object has no attribute 'rfind'

Question

My application runs fine in one computer but when I run the same application in another I get the error:

Traceback (most recent call last):
  File "./th.py", line 98, in browse_file2
    self.textEdit_2.append(str(os.path.basename(p)))
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/posixpath.py", line 121, in basename
    i = p.rfind('/') + 1
AttributeError: 'QString' object has no attribute 'rfind'

I have seen a similar error here . According to this, I need to typecast parameter to 'QString' datatype and I am doing that.The part of script that is having error is:

def browse_file(self):
    #files handling


    caption="Open File"
    directory='./'
    filter_mask="fastq files (*.fastq)"
    self.textEdit.setText("")
    f_1=(QFileDialog.getOpenFileNames(None, caption, directory, filter_mask))
    #for st in f_1:
    for p in f_1:
     self.textEdit.append(str(os.path.basename(p)))
    global R1
    R1=f_1

        #if textEdit.toPlainText


def browse_file2(self):
    #files handling
    caption="Open File"
    directory='./'
    filter_mask="fastq files (*.fastq)"
    f_2=(QFileDialog.getOpenFileNames(None, caption, directory, filter_mask))
    for p in f_2:
     self.textEdit_2.append(str(os.path.basename(p)))
     global R2
     R2=f_2

Can someone please tell what may be the possible cause of this error? Let me know if you need any other part of code. Thanks in advance.

Answer 1

When pyqt first wrapped Qt , they kept the QString class instead of casting it to native python strings (ie. str ). Most python libraries that operate on strings (like os.path ) expect str or unicode objects, not QString 's. This means that you constantly have to type-cast all the return values from pyqt

text = unicode(mywidget.text())

Fortunately, pyqt has newer versions of the api that automatically do the type-casting for you. You just need to tell it to use the newer api. At the beginning of your python code, before you do any other imports, you can do this

import sip
sip.setapi('QString', 2)

There are newer api's for a number of objects as well.