Python Gutenberg E-text Project

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3. Browsing E-texts

A primary function of PyGETS is to help users efficiently browse through the thousands of e-texts available from Project Gutenberg. The following sections describe the use of browsing features provided by PyGETS.

3.1. Contents Display Area

PyGETS displays Project Gutenberg contents information in the large viewing area which occupies the right side of the application window. Data is shown under five category fields: Release, Version, Type, Author, and Title. An example illustration of a partial contents display area is shown in the figure below.

Several options are available to adjust the appearance of data presented in the contents display area.

3.1.1. Sorting by category

Data in the contents display area can be sorted alphabetically for each category by placing the mouse cursor over a category heading, such as Author, and left mouse clicking. Sorting will alternate between ascending and descending sorts with each mouse click. For example, clicking on the Release category heading would sort all content display items by the year of their release.

3.1.2. Category widths

PyGETS attempts to automatically size the width of columns used for category viewing to fit the largest data string within each category. Sometimes this results in significant pieces of data being hidden from view, particularly in the Title category placed at the far right side.

To correct problems with category widths, users can adjust the relative widths of data columns by positioning the mouse cursor on the line segment separating one column heading from another (the mouse cursor will change to a double headed arrow when properly positioned) and dragging the border to the left or right while holding down the left mouse button.

3.1.3. Window size

Users may also control the amount of information viewable in the contents display area by making adjustments to the main application window size. Increasing window size will create more room for displaying contents data. Please refer to the documentation section on window position and size for more information on adjusting window size.

3.2. Filter Controls

Filter controls provide a mechanism for defining subsets of contents data to be displayed. The default action of a filter with no specified constraints is to allow all available data to be displayed. Activating a filter pattern restricts display output to only data containing matches to all active filters. For example, entering the string "Twain" in the Author filter field and the string "Tom" in the Title filter field would limit contents display to only entries where "Twain" appeared somewhere in the author name and "Tom" appeared somewhere in the title string.

Filter patterns for author, title, and release year fields use regular expressions. In general, regular expressions are a very powerful way to specify patterns of characters which can be used for matching and searching in text strings. A description of regular expressions as used in PyGETS can be found at http://www.amk.ca/python/howto/regex/regex.html.

Most users of PyGETS will only need to know a few basics about regular expressions to get results they expect. A regular expression consisting of a simple text value, such as "Tom", will match any text string containing that value. Thus, the regular expression "Tom" would match with both "Tom Grogan" and "Tale of Tommy Fox, The". The special character "^" at the beginning of a regular expression signifies the remaining pattern must appear at the beginning of a text string. Consequently, "^Tom" as a regular expression would match "Tom Grogan", but not "Tale of Tommy Fox, The".

3.2.1. Author

A regular expression entered into the "Author" field will limit items shown in the contents display area to those whose author strings match with the filter expression. Filtering will be initiated and new contents displayed when either the Enter key on the keyboard is pressed after changing the filter field contents, or the Select button is clicked with the mouse.

3.2.2. Title

A regular expression entered into the "Title" field will limit items shown in the contents display area to those whose title strings match with the filter expression. Filtering will be initiated and new contents displayed when either the Enter key on the keyboard is pressed after changing the filter field contents, or the Select button is clicked with the mouse.

3.2.3. Release year

A regular expression entered into the "Release Year" field will limit items shown in the contents display area to those whose release year matches with the filter expression. Filtering will be initiated and new contents displayed when either the Enter key on the keyboard is pressed after changing the filter field contents, or the Select button is clicked with the mouse.

3.2.4. File type

Items shown in the contents display area can be limited to specific e-text formats with the "File Type" pull-down list control. Selecting "All files" from the list allows all file types to be shown. Filtering will be initiated and new contents displayed when a file type from the list is selected, or the Select button is clicked with the mouse.

3.3. Single Field Views

PyGETS supports browsing the contents of individual categories with single-field views. Single-field views show non-redundant values for a single category of e-text information, such as author names. They are useful for providing easy-to-view summaries of material that are available from Project Gutenberg.

During single-field views, previously described methods for category sorting and filtering remain available to the user. An example of combining these methods to perform a more complex browsing function includes the steps: (1) enter "^T" as an author filter pattern to show only authors whose last names begin with the letter "T", (2) switch to single-field viewing of author names, and (3) click on the Author column heading to sort the displayed values alphabetically.

3.3.1. Authors view

Viewing of only author names is invoked with the View->Authors menu command.

3.3.2. Titles view

Viewing of only titles is invoked with the View->Titles menu command.

3.3.3. Releases view

Viewing of only release years is invoked with the View->Releases menu command.

3.3.4. Types view

Viewing of only e-text file types is invoked with the View->Types menu command.

3.3.5. All view

Returning to viewing all categories is invoked with the View->All menu command.