These are letters CR and LF on black background at the end of the lines. When you select View -> Show Symbol -> Show All Characters, you will see, in addition to text some extra symbols. There are two lines of text in the file, with small orange dots in place of whitespaces between words. End-of-line and other non-printable charactersĭownload file from here, save it in your course directory and open in Notepad++. Notepad++ is a plain text editor with many features, today we will use only a few to learn more about the nature of text files. Please install the English language version. You can get it here, you will probably want to install the newest 64-bit version. For the rest of the class we'll assume that you have Notepad++ installed on your system. If you use Mac or Linux you should contact your course instructor for alternatives. In this class we'll use Notepad++ for Windows. To explore text files in more detail we need an appropriate tool. After saving the file as text, we can see its content in Notepad: Obviously there's something more to learn about text files. Interesting things appear when we ask Word to save this as text file - there are a few questions to answer, some choices related to encoding and end of lines. Only when we ask MS Word to save this file as text (try it under Save As.) we get a text file per se. When we open the same file in Windows Notepad, dedicated for plain text, we see this:

When opened in MS Word the file looks like this: To make things confusing, files we usually open and save in one of the most popular text editing program, MS Word, are actually not text files, but rather binary files containing text. Therefore, an understanding of their structure, types and quirks is essential for any biologist. Text files (sometimes called also plain text) are commonly used for storing and exchanging between programs various types of information. The distinction between text and binary files may, at the beginning, seem a bit vague, but hopefully things will become clearer as we move on. The content of binary files, on the contrary, is not human readable, but to convey information meaningful for the user it has to be interpreted by a dedicated program (or run, if it's an executable file).

Loosely speaking, text files contain lines of text, very little else, and are human readable. End-of-line and other non-printable charactersĪt the very basic level, there are two types of computer files: text files and everything else, usually called binary files.

Class 2 Text files, text editors and regular expressions

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