Saving and Loading Text Files in Java Encode code-128c in Java Saving and Loading Text Files

How to generate, print barcode using .NET, Java sdk library control with example project source code free download:

Saving and Loading Text Files generate, create barcode 128 none with java projects Windows Forms The error ha j2ee code 128c ndling is almost identical to what we have seen before, only this time we include the line number where the error occurred.. Writing and Reading Using the codecs Module An alternati code 128 barcode for Java ve to using the PyQt classes is to use Python s built-in and standard library classes for writing and reading text les. Files can be written and read directly using the file class, but if we want to specify the encoding, we must use the codecs module instead..

def saveText (self): error = None fh = None try: fh =, "w", CODEC) for key, movie in self.

__movies: fh.write(u"{{MOVIE}} %s\n" % unicode(movie.title)) fh.

write(u"%d %d %s\n" % (movie.year, movie.minutes, movie.

acquired.toString(Qt.ISODate))) fh.

write(u"{NOTES}") if not movie.notes.isEmpty(): fh.

write(u"\n%s" % unicode(movie.notes)) fh.write(u"\n{{ENDMOVIE}}\n").

We have used barcode 128 for Java exactly the same text format as we used when writing with a QTextStream, so the code is very similar to saveQTextStream(). We open the le using the function rather than the open() function; we do not have to specify a binary ag.

We have omitted the code from the except block to the end since it is the same as we have seen before.. def loadText (self): error = None fh = None try: fh =, "rU", CODEC) self.

clear(False) lino = 0 while True: title = year = minutes = acquired = notes = None line = fh.readline() if not line: break lino += 1 if not line.startswith("{{MOVIE}}"): raise ValueError, "no movie record found" else: title = QString(line[len("{{MOVIE}}"):].

strip()). 8. Data Handling and Custom File Formats We have show n only the rst few lines of the loadText() method that corresponds to saveText(). This is because the method uses the same algorithm and almost the same code as the loadQTextStream() method. The only signi cant differences are due to the fact that we read in the lines as Python unicodes, so we must convert the title and notes to QStrings.

Also, Python keeps the newlines rather than discarding them, and returns an empty string to signify that the end of the le has been reached, so we must slightly modify the code to account for this. For the integers we can use Python s int() function rather than the intFromQStr() function we needed for QStrings. We have chosen to read back in rU mode, which stands for read universal newlines , rather than plain r mode, which stands for read .

This just means that the lines will be read correctly even if written on, say, Linux, and read back on say, Windows, even though the two operating systems use different line-ending conventions.. Saving and Loading XML Files Both PyQt an d the Python standard library can read and write XML les. PyQt provides two parsers for reading, and can write XML using its QDomDocument class. PyQt 4.

3 adds two new XML classes. The QXmlStreamReader class is lightweight like SAX, but easier to use, and the QXmlStreamWriter class is much easier and more ef cient for writing than writing by hand or using DOM. The Python standard library also provides extensive XML support, but in this section we will con ne ourselves to the functionality offered by the PyQt library, since Python s XML classes are well covered by Python s documentation and in such books as Python and XML and XML Processing in Python.

XML formats tend to be a lot more verbose than plain text formats, and not so easy for humans to read. On the other hand, encoding issues are taken care of, so hand editing can be more reliable than with plain text, and the parsing of the overall le structure is usually a lot easier using a suitable XML library than for plain text les. XML formats are generally simpler to extend than either binary or plain text formats, although care must be taken when writing XML to ensure that data does not contain XML meta-characters.

Writing XML is straightforward, but reading it requires the use of a parser. There are two very different and widely used XML parser APIs: DOM (Document Object Model), which loads entire XML documents into memory and is well suited to editing a document s structure, and SAX (Simple API for XML), which works incrementally, so is less resource-hungry and is suitable for searching and processing XML documents. We will show both parsers in action.

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