You can read a file in Ruby like this: Open the file, with the open method. Read the file, the whole file, line by line, or a specific amount of bytes. Close the file, with the close method.
Always close a file that you open. In the case of a file open for writing, this is very important and can actually prevent lost data. File implements a readlines method that reads an entire file into an array, line by line. Both class methods open and readlines belong to the IO class, whose sub-class is File.
This simple example shows you how to create a new file, and write a simple line of text into it. You need to know how to open files and set permissions to use them effectively in your Ruby programs. You don’t want to inadvertently overwrite a file instead of appending to it, else you’ll loose your data.Analyze Apache log file - count localhost in Ruby Pretty printing complex data structures in Ruby - like Data::Dumper in Perl The 14 most important Ruby Resources.Ruby Console: Puts, Print and stdin Use the console window. Call the puts, p, print and stdin.readline methods.. We can thus use many print statements, one after another, on a single line. But we must also print a newline manually. Tip: Print() is a good choice for lines that are built up in many steps. We can avoid concatenating strings.
Reading a file in one line - ruby. GitHub Gist: instantly share code, notes, and snippets.Read More
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Before we get started, remember this: the way a file works, once a line has been read, it doens’t show up again; you’re working your way through the file. At any point, you can use the f.rewind method to go back to the beginning of the file.Read More
Loops in Ruby are used to execute the same block of code a specified number of times. This chapter details all the loop statements supported by Ruby. Ruby while Statement Syntax while conditional (do) code end Executes code while conditional is true.Read More
Tcl provides an easy way to open and read the lines of a file. Check out these code snippets that demonstrate how to read and write files with Tcl programming language.Read More
FileWriter is a convenience class for writing character files. The constructors of this class assume that the default character encoding and the default byte-buffer size are acceptable. To specify these values yourself, construct an OutputStreamWriter on a FileOutputStream.Read More
Create a String to store the file name; Create a new Hash; Open the file in read-only mode; Read each line in the file, one line at a time; Split each line into words (words separated by spaces) Put the word and the word frequency into the Hash (the word is the key, the frequency is the value) Print the hash, with the results sorted by the hash.Read More
The file opens at the line where the object definition begins. IPython will honor the environment variable PAGER if set, and otherwise will do its best to print the file in a convenient form. If the given argument is not an object currently defined, IPython will try to interpret it as a filename (automatically adding a .py extension if needed).Read More
When the file size reaches to MBs or in GB, then the right idea is to get one line at a time. Python readline() method does this job efficiently. It does not load all data in one go. The readline() reads the text until the newline character and returns the line.Read More
So, in this article we have explored ways to read a text file line-by-line in two ways, including a way that I feel is a bit more Pythonic (this being the second way demonstrated in forlinein.py). To wrap things up I presented a trivial application that is potentially useful for reading in and preprocessing data that could be used for text analytics or sentiment analysis.Read More