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c# code to generate barcode Download at in C#.NET
Download at Creating QR In Visual C# Using Barcode encoder for .NET framework Control to generate, create Quick Response Code image in VS .NET applications. www.OnBarcode.comQR Decoder In Visual C# Using Barcode scanner for .NET framework Control to read, scan read, scan image in .NET applications. www.OnBarcode.comCh apt er 9 FIL eS a ND Da ta B a S eS
Paint ANSI/AIM Code 39 In Visual C# Using Barcode creation for VS .NET Control to generate, create Code39 image in Visual Studio .NET applications. www.OnBarcode.comGenerate 2D Barcode In Visual C#.NET Using Barcode encoder for .NET framework Control to generate, create 2D image in .NET applications. www.OnBarcode.comYou can also do this: array_of_lines = File.readlines(filename) Simple! Generally, you should try to use these shortcut methods wherever possible, as they result in shorter, easier-to-read code, and you don t have to worry about closing the files. Everything is taken care of for you in one step. Of course, if reading a file line by line is necessary (perhaps if you re working with extremely large files), then you can use the techniques demonstrated earlier in this chapter for reading line by line. Printing Data Matrix 2d Barcode In C#.NET Using Barcode generation for .NET Control to generate, create DataMatrix image in VS .NET applications. www.OnBarcode.comCode-128 Encoder In Visual C#.NET Using Barcode generation for .NET Control to generate, create Code 128 image in .NET framework applications. www.OnBarcode.comYour position Within a File
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Generally, you can mirror most of the techniques used to read files when writing to files. For example: File.open("text.txt", "w") do |f| f.puts "This is a test" end This code creates a new file (or overwrites an existing file) called text.txt and puts a single line of text within it. Previously, you ve used puts on its own to output data to the screen. However, when used with a File object, puts writes the data to the file instead. Simple! The "w" passed as the second argument to File.open tells Ruby to open the file for writing only, and to create a new file or overwrite what is already in the file. This is in contrast with the "r" mode used earlier when opening a file for reading only. However, you can use several different file modes, as covered in Table 9-1. table 9-1. File Modes Usable with File.new File Mode
r r+ w w+ a a+ b
properties of the I/O Stream
Read-only. The file pointer is placed at the start of the file. Both reading and writing are allowed. The file pointer is placed at the start of the file. Write-only. A new file is created (or an old one overwritten as if new). Both reading and writing are allowed, but File.new creates a new file from scratch (or overwrites an old one as if new). Write (in append mode). The file pointer is placed at the end of the file and writes will make the file longer. Both reading and writing are allowed (in append mode). The file pointer is placed at the end of the file and writes will make the file longer. Binary file mode. You can use it in conjunction with any of the other modes listed. This mode is optional in Ruby 1.8 (except on Windows) but is required in Ruby 1.9 if you are reading files that are not just text. Using the append mode described in Table 9-1, it s trivial to create a program that appends a line of text to a file each time it s run: f = File.new("logfile.txt", "a") f.puts Time.now f.close If you run this code multiple times, logfile.txt will contain several dates and times, one after the other. Append mode is particularly ideal for log file situations where new information has to be added at different times. The read and write modes work in a simple manner. If you want to open a file in a mode where it can be read from and written to at the same time, you can do just that: f = File.open("text.txt", "r+") puts f.gets f.puts "This is a test" puts f.gets f.close
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