Absolute fastest way to save and read data from text file or binary file
To write to a text file, open it using the "w" flag and make sure that you have permission to create the file in the specified directory:.
The convenient writedlm and readdlm functions let you write an array or collection to a file. The elements are separated by tabs unless you specify another delimiter. Here, a colon is used to delimit the numbers:. Since it's so common to use files where the elements are separated with commas rather than tabs CSV files , Julia provides "-csv" versions of these "-dlm" functions, writecsv and readcsv. As ever, refer to the official documentation for options and keywords. There are also a number of Julia packages specifically designed for reading and writing data to files, including DataFrames.
Look through the Julia package directory for these and more. From Wikibooks, open books for an open world.
A Scandal in Bohemia 4 II. A Case of Identity 6 IV. The Boscombe Valley Mystery A Scandal in Bohemia 29 , II. A Case of Identity 35 , IV. The Boscombe Valley Mystery … 62 , the island of Mauritius. As to Miss Violet Hunter , my friend 60 , Holmes , rather to my disappointment , manifested no further 66 , interest in her when once she had ceased to be the centre of one 65 , of his problems , and she is now the head of a private school at 70 , Walsall , where I believe that she has met with considerable success.
Here's how to read from a file on disk using the StorageFile class. The common first step for each of the ways of reading from a file is to get the file with StorageFolder.
Then use a DataReader object to read first the length of the buffer and then its contents. Open a stream for your file by calling the StorageFile. It returns a stream of the file's content when the operation completes.
Get an input stream by calling the GetInputStreamAt method. Put this in a using statement to manage the stream's lifetime. Specify 0 when you call GetInputStreamAt to set the position to the beginning of the stream. Creating Files and Directories This sample shows how to use the Environment class to access the Documents folder where we can create files and directories.
WriteAllText filename, "Write this text into a file" ; Creating a directory is a very similar process: Combine documents, "NewDirectory" ; Directory. CreateDirectory directoryname ; For more information about the System. Serializing Json Working with Json data in a Xamarin. Simply add the NuGet package to your application's project: WriteAllText filename, json ; Refer to Json. Special Considerations Despite the similarities between Xamarin. The contents appear just like the contents of a regular directory, as shown here: Application Directories When your application is installed on a device, the operating system creates its home directory and places your Application Bundle inside.
These directories and their purposes are listed below: If you need to access the content files inside your Application Bundle, the path to this directory is available via the NSBundle. The contents of this directory can be made available to the user through iTunes file sharing although this is disabled by default. As long as sensitive files remain hidden, these files will not be exposed and potentially moved, modified, or deleted by iTunes if file sharing is enabled in a future version.
You can use the Environment. MyDocuments method to get the path to the Documents directory for your application. The contents of this directory are backed up by iTunes. The contents of this directory are never exposed to the user via iTunes. You can create your own subdirectories in Library; however, there are already some system-created directories here that you should be aware of, including Preferences and Caches. The contents of this directory except for the Caches subdirectory are backed up by iTunes.
Custom directories that you create in Library will be backed up. Do not create these files directly. Instead, use the NSUserDefaults class.
The application should create and delete these files as needed and be able to re-create these files if necessary. The contents of this directory are NOT backed up by iTunes, which means they will not be present if the user restores a device, and they may not be present after an updated version of your application is installed.
For instance, in case your application can't connect to the network, you might use the Caches directory to store data or files to provide a good offline experience. To conserve space, files should be deleted when they are no longer required. The operating system may also delete files from this directory when an application is not running. The contents of this directory are NOT backed up by iTunes. For example, the tmp directory might be used to store temporary files that are downloaded for display to the user such as Twitter avatars or email attachments , but which could be deleted once they've been viewed and downloaded again if they are required in the future.
This screenshot shows the directory structure in a Finder window: Accessing Other Directories Programmatically The earlier directory and file examples accessed the Documents directory. WriteAllText filename, "Write this text into a file in Library" ; Creating a directory is very similar: Combine library, "NewLibraryDirectory" ; Directory.
CreateDirectory directoryname ; Paths to the Caches and tmp directories can be constructed like this: For example, the following screenshot shows the files in selected app shared via iTunes: This screenshot shows how these appear in iTunes: To comply with the iOS Data Storage Guidelines you should limit the amount of data that gets backed up by adhering to the following items: Only store user-generated data, or data that cannot otherwise be re-created, in the Documents directory which is backed-up.
This data still uses up space on the device, so you should manage it carefully and delete it when possible. WriteAllText filename, "This file will never get backed-up. It would need to be re-created after a restore or re-install" ; NSFileManager. You can query the attribute using the GetSkipBackupAttribute method, and you can reset it by calling the SetSkipBackupAttribute method with false , like this: Files The iOS app and the extension can also share files using a common file path given they have been properly configured with the correct entitlements and provisioning: