Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "In the RxPY implementation, operators are methods of the Observable class."

A block of code is set as follows:

Observable.from_(...)
 .filter()
 .distinct()
 .take(20)
 .map(...)

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

argv.subscribe(
    on_next=lambda i: print("on_next: {}".format(i)),
    on_error=lambda e: print("on_error: {}".format(e)),
    on_completed=lambda: print("on_completed"))

Any command-line input or output is written as follows:

$ source venv-rx/bin/activate
(venv-rx)$ pip install rx

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "By definition, any program has to deal with external events through inputs/outputs (I/O)."