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: "We instantiate the CountVectorizer class and pass training_data.data to the fit_transform method of the count_vect object."

A block of code is set as follows:

class Node: 
    def __init__(self, data=None): 
        self.data = data 
        self.next = None

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

def dequeue(self):  
    if not self.outbound_stack: 
        while self.inbound_stack: 
            self.outbound_stack.append(self.inbound_stack.pop()) 
    return self.outbound_stack.pop()

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

0     1      2
0   4.0  45.0  984.0
1   0.1   0.1    5.0
2  94.0  23.0   55.0

Bold: Indicates a new term, an important word, or words that you see on screen.