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• which one consume less resources? opening text file or make an sql query,both a thousand times ?

  - by imin

  hi I've a php website which displays recipes www.trymasak.my, to be exact. The recipes being displayed at the index page is updated about once a day. To get the latest recipes, I just use a mysql query which is something like "select recipe_name, page_views, image from table order by last_updated". So if I got 10000 visitors a day, obviously the query would be made 10000 times a day. A friend told me a better way (in terms of reducing server load) is when I update the recipes, I just put in the latest recipe details (names,images etc) into a text file, and make my page instead of querying a same query for 10,000 times, just get the data from the text file. Is his suggestion really better? If yes, which is the best php command should I use to open, read and close the text file? thanks

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• Why are some programs writing on stderr instead of stdout their output?

  - by Zagorax

  I've recently added to my .bashrc file an ssh-add command. I found that ssh-add $HOME/.ssh/id_rsa_github > /dev/null results on a message "identity added and something else" every time I open a shell. While ssh-add $HOME/.ssh/id_rsa_github > /dev/null 2>&1 did the trick and my shell is now 'clean'. Reading on internet, I found that other command do it, (for example time). Could you please explain why it's done?

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• Java: GatheringByteChannel advantages?

  - by Jason S

  I'm wondering when the GatheringByteChannel's write methods (taking in an array of ByteBuffers) have advantages over the "regular" WritableByteChannel write methods. I tried a test where I could use the regular vs. the gathering write method on a FileChannel, with approx 400KB/sec total in ByteBuffers of between 23-27 bytes in length in both cases. Gathering writes used an array of 64. The regular method used up approx 12% of my CPU, and the gathering method used up approx 16% of my CPU (worse than the regular method!) This tells me it's NOT useful to use gathering writes on a FileChannel around this range of operating parameters. Why would this be the case, and when would you ever use GatheringByteChannel? (on network I/O?) Relevant differences here: public void log(Queue<Packet> packets) throws IOException { if (this.gather) { int Nbuf = 64; ByteBuffer[] bbufs = new ByteBuffer[Nbuf]; int i = 0; Packet p; while ((p = packets.poll()) != null) { bbufs[i++] = p.getBuffer(); if (i == Nbuf) { this.fc.write(bbufs); i = 0; } } if (i > 0) { this.fc.write(bbufs, 0, i); } } else { Packet p; while ((p = packets.poll()) != null) { this.fc.write(p.getBuffer()); } } }

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• Writing at the end of file

  - by user342534

  Hi, I'm working on a system that requires high file I/O performance (with C#). Basically, I'm filling up large files (~100MB) from the start of the file until the end of the file. Every ~5 seconds I'm adding ~5MB to the file (sequentially from the start of the file), on every bulk I'm flushing the stream. Every few minutes I need to update a structure which I write at the end of the file (some kind of metadata). When flushing each one of the bulks I have no performance issue. However, when updating the metadata at the end of the file I get really low performance. My guess is that when creating the file (which also should be done extra fast), the file doesn't really allocates the entire 100MB on the disk and when I flush the metadata it must allocates all space until the end of file. Guys/Girls, any Idea how I can overcome this problem? Thanks a lot!

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• How to write or append to text file using sql?

  - by aron

  Hello, in short i need to convert following C# code into SQL stored procedure foreach (var e in Entity) { if (File.Exists(e.Filename)) File.AppendAllText(e.Filename,e.Content); else File.WriteAllText(e.Filename, e.Content); }

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• How can I modify the application file of an application that is currently running (on Linux)?

  - by Hach-Que

  I have an application running called AppFS. This application has an ext2 filesystem just attached to the end of the file (it's positioned so that the application binary exists in a 1MB spacing area, followed by the ext2 data). Now I've got FUSE embedded in the program and I've managed to extract the filesystem out of the application data into a temporary file so that FUSE can mount / use it. The problem I have now is writing the temporary file back into the application file. I get "Text file busy" presumably because the application has locked itself and won't let writes occur. Is there a way I can force the file to become unlocked so I can write data to it? (It's important to note that I'm not changing the application binary area - just rewriting the ext2 component.) It needs to be unlocked without requiring root permissions (unlocked by the same user who started the application).

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• Read file structure into an array, but only specific files.

  - by dmackerman

  I have a directory structure that looks like this: /expandables - folder - folder - folder - folder - BannerInfo.txt - index.html Each one of the folder has the same exact stucture. One file named BannerInfo.txt and index.html. There are about 250 of these folders if that matters. I want to loop through these folders and store each of the index.html files into an array. Inside of the index.html file is just some simple HTML and Javascript of which I want to read into a string to be displayed later on. I'm struggling with how to filter out only the index.html file from the individual folders. The purpose of this is because I want to randomly select an index.html file and put the contents into a textarea. I thought I could do a simple array_rand() on the returned array and spit out the string. Any ideas?

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• USB device Set Attribute in C#

  - by p19lord

  I have this bit of code: DriveInfo[] myDrives = DriveInfo.GetDrives(); foreach (DriveInfo myDrive in myDrives) { if (myDrive.DriveType == DriveType.Removable) { string path = Convert.ToString(myDrive.RootDirectory); DirectoryInfo mydir = new DirectoryInfo(path); String[] dirs = new string[] {Convert.ToString(mydir.GetDirectories())}; String[] files = new string[] {Convert.ToString(mydir.GetFiles())}; foreach (var file in files) { File.SetAttributes(file, ~FileAttributes.Hidden); File.SetAttributes(file, ~FileAttributes.ReadOnly); } foreach (var dir in dirs) { File.SetAttributes(dir, ~FileAttributes.Hidden); File.SetAttributes(dir, ~FileAttributes.ReadOnly); } } } I have a problem. It is trying the code for Floppy Disk drive first which and because no Floppy disk in it, it threw the error The device is not ready. How can I prevent that?

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• Parsing C# Script into Java

  - by pantaryl

  I'm looking for a way to easily read in a C# file and place it into a Java Object for database storage (storing the class name, functions, variables, etc). I'm making a Hierarchical State Machine AI Building Tool for a game I'm creating and need to be able to import an existing C# file and store it in a database for retrieval in the future. Does anyone know of any preexisting libraries for parsing C# files? Something similar to JavaParser? Thanks everyone! EDIT: This needs to be part of my Java Project. I'll be loading in the C# files through my Java Application and saving it into my db4o database.

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• Naming a file downloaded from url in iPhone

  - by hgpc

  I would like to save a file downloaded from the internet in iPhone. Can I use the url as the file name? If not, what transformation should I apply to the url to obtain a valid file name? I need to find the local copy of the file later using its url.

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• How do I read and write to a file using threads in java?

  - by WarmWaffles

  I'm writing an application where I need to read blocks in from a single file, each block is roughly 512 bytes. I am also needing to write blocks simultaneously. One of the ideas I had was BlockReader implements Runnable and BlockWriter implements Runnable and BlockManager manages both the reader and writer. The problem that I am seeing with most examples that I have found was locking problems and potential deadlock situations. Any ideas how to implement this?

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• Using FILE_FLAG_NO_BUFFERING will return noticeable speed gain?

  - by 9dan

  Recently noticed detail description of FILE_FLAG_NO_BUFFERING flag in MSDN, and read several Google search results about unbuffered I/O in Windows. http://msdn.microsoft.com/en-us/library/aa363858(v=vs.85).aspx I wondering now, is it really important to consider unbuffered option in file I/O programming? Because many programs use plain old C stream I/O or C++ iostream, I didn't gave any attention to FILE_FLAG_NO_BUFFERING flag before. Let's say we are developing photo explorer program like Picasa. If we implement unbuffered I/O, could thumbnail display speed show noticeable difference in ordinary users?

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• C++ how to store integer into a binary file??

  - by blaxc

  i gt a struct with 2 integer, i want to store them in a binary file and read it again... here is my code... struct pw { int a; int b; }; void main(){ pw* p = new pw(); pw* q = new pw(); std::ofstream fout(ADMIN_FILE, ios_base::out | ios_base::binary | ios_base::trunc); std::ifstream fin(ADMIN_FILE, ios_base::in | ios_base::binary); p->a=123; p->b=321; fout.write((const char*)p, sizeof(pw)); fin.write((char*)q, sizeof(pw)); fin.close(); cout<< q->a << endl;} my output is 0. anyone can tell me what is the problem?

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• Randomly select file in PHP

  - by user201140

  I'd like to use the 'include' keyword in php to randomly select a file from a folder and output the contents. How would I do this? Thanks.

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• FileInput Help/Advice

  - by user559142

  I have a fileinput class. It has a string parameter in the constructor to load the filename supplied. However it just exits if the file doesn't exist. I would like it to output a message if the file doesn't exist - but not sure how.... Here is the class: public class FileInput extends Input { /** * Construct <code>FileInput</code> object given a file name. */ public FileInput(final String fileName) { try { scanner = new Scanner(new FileInputStream(fileName)); } catch (FileNotFoundException e) { System.err.println("File " + fileName + " could not be found."); System.exit(1); } } /** * Construct <code>FileInput</code> object given a file name. */ public FileInput(final FileInputStream fileStream) { super(fileStream); } } And its implementation: private void loadFamilyTree() { out.print("Enter file name: "); String fileName = in.nextLine(); FileInput input = new FileInput(fileName); family.load(input); input.close(); }

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• watch / read a growing log file with ruby

  - by KingInk

  I have a log file that is constantly growing, how can I watch and parse it via a ruby script. The script will parse each new line as it is written to the file and output something to the screen when the new line contains the string 'ERROR'

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• Split a binary file into chunks c++

  - by L4nce0

  I've been bashing my head against trying to first divide up a file into chunks, for the purpose of sending over sockets. I can read / write a file easily without splitting it into chunks. The code below runs, works, kinda. It will write a textfile and has a garbage character. Which if this was just for txt, no problem. Jpegs aren't working with said garbage. Been at it for a few days, so I've done my research, and it's time to get some help. I do want to stick strictly to binary readers, as this need to handle any file. I've seen a lot of slick examples out there. (none of them worked for me with jpgs) Mostly something along the lines of while(file)... I subscribe to the, if you know the size, use a for-loop, not a while-loop camp. Thank you for the help!! vector<char*> readFile(const char* fn){ vector<char*> v; ifstream::pos_type size; char * memblock; ifstream file; file.open(fn,ios::in|ios::binary|ios::ate); if (file.is_open()) { size = fileS(fn); file.seekg (0, ios::beg); int bs = size/3; // arbitrary. Actual program will use the socket send size int ws = 0; int i = 0; for(i = 0; i < size; i+=bs){ if(i+bs > size) ws = size%bs; else ws = bs; memblock = new char [ws]; file.read (memblock, ws); v.push_back(memblock); } } else{ exit(-4); } return v; } int main(int argc, char **argv) { vector<char*> v = readFile("foo.txt"); ofstream myFile ("bar.txt", ios::out | ios::binary); for(vector<char*>::iterator it = v.begin(); it!=v.end(); ++it ){ myFile.write(*it,strlen(*it)); } }

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• Operator Overloading << in c++

  - by thlgood

  I'm a fresh man in C++. I write this simple program to practice Overlaoding. This is my code: #include <iostream> #include <string> using namespace std; class sex_t { private: char __sex__; public: sex_t(char sex_v = 'M'):__sex__(sex_v) { if (sex_v != 'M' && sex_v != 'F') { cerr << "Sex type error!" << sex_v << endl; __sex__ = 'M'; } } const ostream& operator << (const ostream& stream) { if (__sex__ == 'M') cout << "Male"; else cout << "Female"; return stream; } }; int main(int argc, char *argv[]) { sex_t me('M'); cout << me << endl; return 0; } When I compiler it, It print a lots of error message: The error message was in a mess. It's too hard for me to found useful message sex.cpp: ???‘int main(int, char**)’?: sex.cpp:32:10: ??: ‘operator<<’?‘std::cout << me’????? sex.cpp:32:10: ??: ???: /usr/include/c++/4.6/ostream:110:7: ??: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostre

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• Creating a file path in C#

  - by Jason

  So I'm trying to create a path in C#. I use Environment.Machinename and store it a variable serverName. Then I create another string variable and have some other path extension in there. Here is my code so far: string serverName = Environment.MachineName; string folderName = "\\AlarmLogger"; No matter what I do I can't seem to obtain only one backslash prior to AlarmLogger. Any ideas how I can specify a path in C#? Edit: I'm wondering if my code doesn't seem to want to paste correctly. Anyways when i paste it I only see one backslash but my code has two. Because of the escape character sequence. But something like string test = @"\" + serverName + folderName doesn't seem to want to work for me.

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• problem with f.readline()?

  - by kaushik

  I am reading one line at a time from a file, but at the end of each line it adds a '\n'. example: line is: 094 234 hii but my input is: 094 234 hii\n I want to read line by linem but I don't need to keep the newlines... My goal is to read a list from every line: I need ['094','234','hii'], not ['094','234','hii\n'] Any advice?

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• related to java file handling.

  - by sadia

  In Java how can I take the data of my file on my display screen? I want to use data in my file and also want that data to be displayed on my output screen when I execute my program. Can any body please help by providing me such example in Java language. Thank you!

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• Writing different structs to a file in C++? [on hold]

  - by user58053

  I need a way to write structures of three different kinds to a binary file, which later has to be searched. (As in, for example, struct A has two fields, an int and a char; struct B has int and a long; I need to output all structures whose int equals the one given from keyboard). I understand how to write structs of the same kind to a file and how to search them, but here I am just lost, best thing I came up with is declaring a struct containing all possibly needed fields and leaving the ones I don't need empty, but it really feels wrong, there HAS to be a better way to do that. I've read about binary files and could not find anything relevant, most examples and tutorials deal with writing one data type. Could anyone point me in the right direction? EDIT: I am looking for what @Jerry_coffin called database mode, and will probably use one of the existing database systems for that, best way to go, probably. Thank you everybody for the suggestions

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• What Is The Replace Function In Python

  - by Eva

  I want to write a python code that open a text file and Replace with a word that i want send to it . May you give me an example ? Thanks .

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• getting directory name in java

  - by Codenotguru

  how to get the directory name for a particular file on the drive in java? for example i have a test.java under a test directory on my D drive.how do i find the directory name for this test.java?

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• How to switch data pins on/off on parallel port?

  - by Matt

  I want to simply switch certain data pins on and off, so that they can control a set of relays. I'm not asking about the hardware bit (should be easy), but I don't know where to begin writing the software. I don't want a high level library that can send bytes to a device - I literally want to switch on/off certain pins. I'm running Linux and I want to do this in Java, so would I just need a library? It would be nice if the library has good documentation and is easy to use, but if not then a short example code will help me get started.

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