Objective-C: Reading a file line by line -

-

What is the proper way to deal with large text files in Objective-C? Suppose I have to read each row separately and treat each line as an NSString. What is the most effective way to do this?

A solution is using the NSString method: 

  + (id) stringWithContentsOfFile: (NSString *) path encoding: (NSStringEncoding) Anch Error: (NSError ** ) Error

and then split the line with a new line separator, and then repeat the elements again in the array. However, it is quite inefficient. There is no easy way to treat the file as a stream, instead of just reading it at all, instead of being told in each line? Just like Java's Java.O.Buffard Reader.

This is a great question I think is a good example of @didric The answer is, though it is unfortunate that there is no mechanism for what you really want to do in Cocoa.

You have the amount of n bytes (very similar to java.io.bufferedReader ), but you can convert it to a NSString by yourself , Then Scan for Newline (or whatever other delimiter), and save any next character, or more characters to read next, if no new line has yet been read. (You can read a NSData , which you can convert to a NSString , but this is essentially the same process.)

Apple is the one who can help fill out the details, and if you are going to deal with the uint8_t * buffers, can also help.

If you want to read the wire in this way (especially in different parts of your program) it would be a good idea to explain this behavior in a class that details for you, or NSInputStream (this can sub-clinging) and by adding methods that allow you actually read what you want.

For the record, I think it will be a good feature to add, and I will file an increment request for something like that which makes it possible. : -)

Edit: This request expires already exists for a radar 2006 (for ADR-internal people (rdar: // 4742914).


Comments

Post a Comment

Popular posts from this blog

c++ - Linux and clipboard -

-
After selecting the copies of the buffer in Linux, after the text, we can click and paste the button between the mouse. I think there is a special buffer for this, I want to use it. Programming Language: C ++ Your Library: Qt Thanks. There is just one more correct answer than Paul Dixon, which answers your needs: / P > QClipboard * clipboard = QApplication :: clipboard (); CastString Selected Text = Clipboard-> Text (QClipboard :: Selection);
Read more

What is expire header and how to achive them in ASP.NET and PHP? -

-
I have examined the performance statistics of my website today. I have received a warning (or error may occur) that is given below Add Terminal Headers Here are 15 static components without a 15-futures end date * (no end) Http://www.example.com/video/css/global.css * (no time limit) http://www.example.com/video/js/global.js * (no expiration ) Http: //www.example.com/video/images/main-bg.png what it means and how to achieve it both in PHP and ASP.Net. I am on a shared hosting server, so please tell me some ways to use the code, because I can not make any modifications at the end of the server. If I expire the header, then there is no chance that if I make changes to the CSS, then the user will not be able to remove them immediately because CSS and other files have a fixed time limit (1 month, week ) Are cached for. Is Is there any harm to using PHP? $ time = time () + 3 * 24 * 60 * 60; // 3 day headings ('End:'. GMDAT ('D, D MYH: i: s \ g \ m \ t',
Read more

sql server - How can I determine which of my SQL 2005 statistics are unused? -

-
After a few years, one of my biggest databases has deposited 73 figures out of its largest tables. With Indexes, I can run many types of reports and queries, how often / heavily specific indexes are used. What is an equivalent for data? We are running SQL 2005. To make statistics automatically managed and honest, I would like to "update statistics", "create statistics" and There is no information about any management except "drop statistics" orders. In theory, UPDATE should handle the addition and removal of statistical data. In addition, I've never heard about the amount of storage or storage taking in large amounts, so I'm not sure whether there is any reason for the alarm or not. If you are seeing a potential problem, then I would suggest running an update before, if it does not clean it, it is leaving and then it appears to be safe operation (because it is the only query optimizer Is for). I will not leave "left" in the
Read more